United Airlines (UAL) 424B5Prospectus supplement for primary offering

execution risks associated with our strategic operating plan;

changes in our network strategy or other factors outside our control resulting in less economic aircraft orders, costs related to modification or termination of aircraft orders or entry into less favorable aircraft orders, as well as any inability to accept or integrate new aircraft into our fleet as planned;

any failure to effectively manage, and receive anticipated benefits and returns from, acquisitions, divestitures, investments, joint ventures and other portfolio actions, as well as related costs or other issues, or related exposures to unknown liabilities or other issues or underperformance as compared to our expectations;

the adverse impacts of the ongoing COVID-19 global pandemic on our business, operating results, financial condition and liquidity;

adverse publicity, harm to our brand, reduced travel demand, potential tort liability and voluntary or mandatory operational restrictions as a result of an accident, catastrophe or incident involving us, our regional carriers, our codeshare partners or another airline;

the highly competitive nature of the global airline industry and susceptibility of the industry to price discounting and changes in capacity, including as a result of alliances, joint business arrangements or other consolidations;

our reliance on a limited number of suppliers to source a majority of our aircraft and certain parts, and the impact of any failure to obtain timely deliveries, additional equipment or support from any of these suppliers;

disruptions to our regional network and United Express flights provided by third-party regional carriers;

unfavorable economic and political conditions in the United States and globally;

reliance on third-party service providers and the impact of any significant failure of these parties to perform as expected, or interruptions in our relationships with these providers or their provision of services;

extended interruptions or disruptions in service at major airports where we operate and space, facility and infrastructure constraints at our hubs or other airports;

geopolitical conflict, terrorist attacks or security events (including the continuation of the suspension of our overflying in Russian airspace as a result of the Russia-Ukraine military conflict and to Tel Aviv as a result of the Israeli-Palestinian military conflict and an escalation of the broader economic consequences of the conflicts beyond their current scope);

any damage to our reputation or brand image;

contained in the warrants and described in this prospectus supplement, when we issue additional shares of our common stock that we are permitted or required to issue in any future offerings or under outstanding convertible securities, options and warrants and under our stock option plans or other employee or director compensation plans.

of us, even if a change in control would be beneficial to our existing stockholders. These provisions could also impede a merger, takeover or other business combination involving us or discourage a potential acquirer from making a tender offer for our common stock, engaging in a proxy fight or conducting open market purchases, which, under certain circumstances, could reduce the market price of our common stock.

The closing price for our common stock has varied between a high of $57.61 on July 21, 2023 and a low of $33.90 on October 27, 2023 in the twelve-month period ended on November 17, 2023. Volatility in the market price of our common stock may prevent holders from selling the shares at or above the prices paid for them. The market price of our common stock could fluctuate significantly for various reasons which include:

the market reaction to another COVID-19-like pandemic and our responses thereto;

the sale of substantial amounts of our common stock;

changes in the prices or availability of oil or jet fuel;

our quarterly or annual earnings or those of other companies in our industry;

the public’s reaction to our press releases, our other public announcements and our filings with the SEC;

changes in our earnings or recommendations by research analysts who track our common stock or the stock of other airlines;

changes in general conditions in the United States and global economy, financial markets or airline industry, including those resulting from changes in fuel prices or fuel shortages, war, incidents of terrorism, pandemics or responses to such events;

changes in the competitive landscape for the airline industry, including any changes resulting from industry consolidation whether or not involving our Company;

our liquidity position; and

the other risks described or referred to in these “Risk Factors.”

In addition, in recent periods, the stock market has experienced extreme declines and volatility. This volatility has had a significant negative impact on the market price of securities issued by many companies, including us and other companies in our industry.

The sale or availability for sale of substantial amounts of our common stock could adversely impact its price. Our certificate of incorporation authorizes us to issue 1,000,000,000 shares of common stock. On November 15, 2023, there were 328,016,915 shares of common stock outstanding. Accordingly, a substantial number of shares of our common stock are outstanding and available for sale in the market. In addition, we may be obligated to issue additional shares of common stock upon the conversion of outstanding convertible securities, including the warrants offered hereby, or in connection with employee benefit plans (including any equity incentive plans and employee stock purchase plans).

In the future, we may decide to raise capital through offerings of our common stock, additional securities convertible into or exercisable or exchangeable for common stock, or rights to acquire these securities or common stock. The issuance of additional shares of common stock or additional securities convertible into or exercisable or exchangeable for common stock could result in dilution of existing stockholders’ equity interests in the Company. Issuances of substantial amounts of common stock, or the perception that such issuances could occur, may adversely affect prevailing market prices for our common stock and we cannot predict the effect this dilution may have on the price of our common stock.

any employee benefit plan of UAL or of any subsidiary of UAL or any entity or trustee holding (or acting in a fiduciary capacity in respect of) shares of capital stock of UAL for or pursuant to the terms of any such plan or for the purpose of funding other employee benefits for employees of UAL or any subsidiary of UAL;

any person or group that, together with its affiliates and associates, as of immediately prior to the first public announcement of the adoption of the Tax Benefits Preservation Plan, beneficially owns 4.9% or more of the outstanding shares of common stock so long as such person or group continues to beneficially own at least 4.9% of the outstanding shares of common stock and does not acquire shares of common stock to beneficially own an amount equal to or greater than the greater of 4.9% and the sum of the lowest beneficial ownership of such person or group since the public announcement of the adoption of the Tax Benefits Preservation Plan plus one share of common stock.

or associates or certain transferees of such Acquiring Person or of any such affiliate or associate, whose Rights automatically become null and void) will have the right to receive, upon exercise, common stock having a value equal to two times the exercise price of the Right.

UAL consolidates with, or merges with and into, any other entity, and UAL is not the continuing or surviving entity;

any entity engages in a share exchange with or consolidates with, or merges with or into, UAL, and UAL is the continuing or surviving entity and, in connection with such share exchange, consolidation or merger, all or part of the outstanding shares of common stock are changed into or exchanged for stock or other securities of any other entity or cash or any other property; or

UAL sells or otherwise transfers, in one transaction or a series of related transactions, 50% or more of UAL’s assets, cash flow or earning power,

then each holder of a Right (except Rights which previously have been voided as described above) will have the right to receive, upon exercise, common stock of the acquiring company having a value equal to two times the exercise price of the Right.

in the event of a stock dividend on, or a subdivision, combination or reclassification of, the Series A Preferred Stock,

if holders of the Series A Preferred Stock are granted certain rights, options or warrants to subscribe for Series A Preferred Stock or convertible securities at less than the current market price of the Series A Preferred Stock or

upon the distribution to holders of the Series A Preferred Stock of evidences of indebtedness or assets (excluding regular quarterly cash dividends) or of subscription rights or warrants (other than those referred to above).

at a price of $0.001 per Right (subject to adjustment and payable in cash, common stock or other consideration deemed appropriate by the Board). Immediately upon the action of the Board authorizing any redemption or at such later time as the Board may establish for the effectiveness of the redemption, the Rights will terminate and the only right of the holders of Rights will be to receive the redemption price.

set forth in the bylaws, by the Secretary, upon the written request of one or more stockholders of record of UAL that together have continuously held, for their own account or on behalf of others, beneficial ownership of at least a 25% aggregate “net long position” ​(as defined in the bylaws) of the outstanding common stock for at least one year prior to the date such request is delivered to UAL.

The following is a general discussion of the material U.S. federal income and certain estate tax consequences of the purchase, exercise, disposition and lapse of warrants to purchase shares of our common stock (such shares, the “warrant shares”) acquired pursuant to this offering and the purchase, ownership and disposition of warrant shares (together with the warrants, the “securities”).

This discussion does not address the U.S. federal tax consequences to an entity treated as a partnership for U.S. federal income tax purposes or to persons investing through such an entity. If an entity treated as a partnership holds securities, the tax treatment of a partner will generally depend on the status of the partner and the activities of the partnership. A partner in a partnership considering an investment in securities should consult its own tax advisors as to the U.S. federal income and estate tax consequences of being a partner in a partnership that purchases, owns or disposes of securities.

This summary assumes that the securities are held as a capital asset (generally, property held for investment). This summary is of a general nature and thus does not address all of the U.S. federal income and estate tax considerations that might be relevant to a holder of securities in light of its particular circumstances or to a holder of securities subject to special treatment under U.S. federal tax laws (such as banks, insurance companies, dealers in securities or other holders of securities that generally mark their securities to market for U.S. federal income tax purposes, foreign governments, international organizations, tax-exempt entities, “controlled foreign corporations,” “passive foreign investment companies,” regulated investment companies, real estate investment trusts, certain former citizens or residents of the United States, or holders of securities that hold securities as part of a straddle, hedging transaction, conversion transaction or integrated transaction or that purchase or sell securities as part of a wash sale for U.S. federal income tax purposes). Furthermore, this summary does not discuss any aspects of U.S. federal gift, state, local or non-U.S. taxation. This summary is based on current provisions of the U.S. Internal Revenue Code of 1986, as amended (the “Code”), U.S. Treasury regulations promulgated or proposed thereunder, judicial opinions, published positions of the U.S. Internal Revenue Service (the “IRS”) and other applicable authorities, all of which are subject to change or differing interpretation, possibly with retroactive effect. Each prospective purchaser of securities is advised to consult its own tax advisor with respect to the U.S. federal, state, local and non-U.S. tax consequences of purchasing, owning and disposing of securities. No assurance exists that the IRS will not challenge any of the tax consequences described herein, and we have not obtained, nor do we intend to obtain, an opinion of counsel with respect to the U.S. federal income or estate tax consequences to a holder of securities of purchasing, owning and disposing of securities.

PROSPECTIVE INVESTORS CONSIDERING THE PURCHASE OF THE SECURITIES SHOULD CONSULT THEIR OWN TAX ADVISORS CONCERNING THE APPLICATION OF U.S. FEDERAL TAX LAWS TO THEIR PARTICULAR SITUATIONS AS WELL AS ANY CONSEQUENCES ARISING UNDER THE LAWS OF ANY OTHER TAXING JURISDICTION AND ANY APPLICABLE TAX TREATY.

For purposes of this discussion, a “U.S. Holder” is a beneficial owner of securities that is treated for U.S. federal income tax purposes as:

an individual who is a citizen or a resident of the United States;

a corporation created or organized under the laws of the United States, any state thereof or the District of Columbia;

an estate the income of which is subject to U.S. federal income taxation regardless of its source; or

a trust (i) the administration of which is subject to the primary supervision of a court within the United States and which has one or more U.S. persons who have the authority to control all substantial decisions of the trust, or (ii) that has a valid election in effect under applicable U.S. Treasury regulations to be treated as a United States person (within the meaning of Section 7701(a)(30) of the Code).

constructive distribution to a U.S. Holder of the warrants if, and to the extent that, such adjustment has the effect of increasing such U.S. Holder’s proportionate interest in our earnings and profits as determined under U.S. federal income tax principles or our assets, depending on the circumstances of such adjustment (for example, if such adjustment is to compensate for a distribution of cash or other property to our shareholders).

If we make distributions on warrant shares, the distributions will be dividends for U.S. federal income tax purposes to the extent paid from current or accumulated earnings and profits. To the extent distributions exceed our current and accumulated earnings and profits, they will constitute a return of capital that will first reduce a U.S. Holder’s basis in the warrant shares (determined separately for each share), but not below zero, and then will be treated as gain from the sale of stock, subject to the tax treatment described below under “—Sale or Other Taxable Disposition of Warrant Shares.”

Dividends paid by us to corporate U.S. Holders will be eligible for the dividends-received deduction, provided that the corporate U.S. Holder receiving the dividends satisfies the holding period and other requirements for the dividends-received deduction. Dividends paid by us to certain non-corporate U.S. Holders (including individuals) will be eligible for U.S. federal income taxation at the rates generally applicable to long-term capital gains for individuals, provided that the non-corporate U.S. Holder receiving the dividends satisfies the applicable holding period and other requirements.

Upon the sale, exchange or other taxable disposition of the warrant shares, a U.S. Holder will generally recognize capital gain or loss equal to the difference between the amount of cash and the fair market value of any property received upon the sale, exchange or other taxable disposition and such U.S. Holder’s adjusted tax basis in the warrant shares. This capital gain or loss will be long-term capital gain or loss if the U.S. Holder’s holding period in such warrant shares is more than one year at the time of the sale, exchange or other taxable disposition. Long-term capital gains recognized by certain non-corporate U.S. Holders, including individuals, generally will be subject to reduced rates of U.S. federal income tax. The deductibility of capital losses is subject to certain limitations.

A U.S. Holder may be subject to information reporting and backup withholding when such holder receives payments on securities (including constructive dividends) or receives proceeds from the sale or other taxable disposition of securities. Certain U.S. Holders are exempt from backup withholding, including C corporations. A U.S. Holder will be subject to backup withholding if such holder is not otherwise exempt and such holder:

fails to furnish the holder’s taxpayer identification number, which for an individual is ordinarily his or her social security number;

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a U.S. Holder’s U.S. federal income tax liability, provided the required information is timely furnished to the IRS. U.S. Holders should consult their tax advisors regarding their qualification for an exemption from backup withholding and the procedures for obtaining such an exemption.

disposition and (y) such Non-U.S. Holder’s holding period with respect to such securities, and, provided that our common stock is regularly traded on an established securities market within the meaning of applicable U.S. Treasury regulations, such Non-U.S. Holder has held, directly or constructively, at any time during said period, more than 5% of our common stock. We do not believe that we are or will become a USRPHC; however, there can be no assurance in that regard.

the highly competitive nature of the global airline industry and susceptibility of the industry to price discounting and changes in capacity, including as a result of alliances, joint business arrangements or other consolidations;

any failure to attract, train or retain skilled personnel, including our senior management team or other key employees;

the monetary and operational costs of compliance with extensive government regulation of the airline industry;

current or future litigation and regulatory actions, or failure to comply with the terms of any settlement, order or arrangement relating to these actions;

costs, liabilities and risks associated with environmental regulation and climate change, including our climate goals;

high and/or volatile fuel prices or significant disruptions in the supply of aircraft fuel;

the impacts of our significant amount of financial leverage from fixed obligations and the impacts of insufficient liquidity on our financial condition and business;

failure to comply with financial and other covenants governing our debt, including our MileagePlus® financing agreements;

the impacts of the phase out of the London interbank offer rate;

limitations on our ability to use our net operating loss carryforwards and certain other tax attributes to offset future taxable income for U.S. federal income tax purposes;

our failure to realize the full value of our intangible assets or our long-lived assets, causing us to record impairments;

dividend of one right (a “Right”) to purchase from UAL one one-thousandth of a share of Series A Preferred Stock to stockholders of record at the close of business on December 14, 2020 (the “Record Date”). Each Right entitles its holder, under the circumstances described below, to purchase from UAL one one-thousandth of a share of Series A Preferred Stock, at an exercise price of $250.00 per Right, subject to adjustment.

the close of business on the tenth (10th) day after the “Stock Acquisition Date” ​(which is defined as (a) the first date of public announcement that any person or group has become an “Acquiring Person,” which is defined as a person or group that, together with its affiliates and associates, beneficially owns 4.9% or more of the outstanding shares of UAL Common Stock (with certain exceptions, including those described below) or (b) such other date, as determined by the Board, on which a person or group has become an Acquiring Person) or

the close of business on the tenth (10th) business day (or such later date as may be determined by the Board prior to such time as any person or group becomes an Acquiring Person) after the commencement of a tender offer or exchange offer that, if consummated, would result in a person or group becoming an Acquiring Person.

UAL or any subsidiary of UAL;

any officer, director or employee of UAL or any subsidiary of UAL in his or her capacity as such;

any employee benefit plan of UAL or of any subsidiary of UAL or any entity or trustee holding (or acting in a fiduciary capacity in respect of) shares of capital stock of UAL for or pursuant to the terms of any such plan or for the purpose of funding other employee benefits for employees of UAL or any subsidiary of UAL;

any person or group, together with its affiliates and associates, whose beneficial ownership of 4.9% or more of the then-outstanding shares of UAL Common Stock will not jeopardize or endanger the availability to UAL of any net operating loss (“NOL”) or other tax attribute, as determined by the Board in its sole discretion prior to the time any person becomes an Acquiring Person (provided that such person will be an Acquiring Person if the Board subsequently makes a contrary determination in its sole discretion, regardless of the reason for such contrary determination); or

any person or group that, together with its affiliates and associates, as of immediately prior to the first public announcement of the adoption of the Tax Benefits Preservation Plan, beneficially owns 4.9% or more of the outstanding shares of UAL Common Stock so long as such person or group continues to beneficially own at least 4.9% of the outstanding shares of UAL Common Stock and does not acquire shares of UAL Common Stock to beneficially own an amount equal to or greater

UAL consolidates with, or merges with and into, any other entity, and UAL is not the continuing or surviving entity;

any entity engages in a share exchange with or consolidates with, or merges with or into, UAL, and UAL is the continuing or surviving entity and, in connection with such share exchange, consolidation or merger, all or part of the outstanding shares of UAL Common Stock are changed into or exchanged for stock or other securities of any other entity or cash or any other property; or

UAL sells or otherwise transfers, in one transaction or a series of related transactions, 50% or more of UAL’s assets, cash flow or earning power,

then each holder of a Right (except Rights which previously have been voided as described above) will have the right to receive, upon exercise, common stock of the acquiring company having a value equal to two times the exercise price of the Right.

in the event of a stock dividend on, or a subdivision, combination or reclassification of, the Series A Preferred Stock,

if holders of the Series A Preferred Stock are granted certain rights, options or warrants to subscribe for Series A Preferred Stock or convertible securities at less than the current market price of the Series A Preferred Stock or

upon the distribution to holders of the Series A Preferred Stock of evidences of indebtedness or assets (excluding regular quarterly cash dividends) or of subscription rights or warrants (other than those referred to above).

may exchange the Rights (other than Rights owned by the Acquiring Person, any of its affiliates or associates or certain transferees of Acquiring Person or of any such affiliate or associate, whose Rights will have become null and void), in whole or in part, at an exchange ratio of one share of UAL Common Stock, or one one-thousandth of a share of Series A Preferred Stock (or of a share of a class or series of Serial Preferred Stock having equivalent rights, preferences and privileges), per Right (subject to adjustment).

other than nominations pursuant to the terms of the Class Pilot MEC Junior Preferred Stock, the Class IAM Junior Preferred Stock or nominations made by or at the direction of the Board or a committee of the Board. In order for any matter to be “properly brought” before a meeting, a stockholder will have to comply with advance notice requirements and provide UAL with certain information. Under UAL’s amended and restated bylaws, the Board may also adopt rules, regulations and procedures for the conduct of stockholder meetings as the Board deems appropriate, and except to the extent inconsistent with such rules, regulations and procedures adopted by the Board, the person presiding at any meeting of stockholders has the right and authority to convene and (for any or no reason) to recess or adjourn the meeting, to prescribe such rules, regulations and procedures and to do all such acts as, in the judgment of such person, are necessary, appropriate or convenient for the proper conduct of the meeting, which may have the effect of precluding the conduct of certain business at a meeting if the rules and regulations are not followed. These procedures and provisions may deter, delay or discourage a potential acquiror from conducting a solicitation of proxies to elect the acquiror’s own slate of directors or otherwise attempting to obtain control of UAL.

the transfer of or exchange the debt securities of any series selected, called or being called for redemption as a whole or the portion being redeemed of any such debt securities selected, called or being called for redemption in part.

to the extent set forth in the prospectus supplement relating thereto. To the extent the issuer of any debt securities conducts operations through subsidiaries of such issuer, the holders of such debt securities (whether or not subordinated debt securities) will be structurally subordinated to the creditors of such subsidiaries except to the extent such subsidiary is a guarantor of such series of debt securities.

trustee, however, may refuse to follow any direction that conflicts with law or the indenture, that the trustee determines is unduly prejudicial to the rights of any other holder of such series of debt securities or that would subject the trustee to personal liability. Prior to taking any action under the indenture, the trustee is entitled to indemnification satisfactory to it in its sole discretion against all losses and expenses caused by taking or not taking such action.

such holder has previously given to the trustee written notice of a continuing event of default with respect to such series of debt securities;

the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made a written request to the trustee to pursue such remedy;

such holder or holders have offered to the trustee security or indemnity satisfactory to the trustee against any loss, liability or expense;

the trustee has not complied with the request within 60 days after receipt of the request and the offer of security or indemnity; and

the holders of a majority in aggregate principal amount of the outstanding debt securities of that series do not give the trustee a direction inconsistent with the request during such 60-day period.

make any change to the percentage of principal amount of the outstanding debt securities of the applicable series the holders of which must consent to an amendment;

reduce the principal amount of, premium, if any, or interest on, or extend the stated maturity or interest payment periods of, such debt security;

make such debt security payable in money or securities other than that stated in such debt security;

make any change that adversely affects such holder’s right to require the applicable issuer to purchase such debt security in accordance with the terms thereof and under the indenture;

impair the right of such holder to institute suit for the enforcement of any payment with respect to such debt securities;

in the case of any subordinated debt security or coupons appertaining thereto, make any change in the provisions of the indenture relating to subordination that adversely affects the rights of such holder under such provisions;

except as provided under “— Satisfaction and Discharge of the Indenture; Defeasance” below or in accordance with a guarantee, release any guarantor of such debt securities from any of its obligations under the guarantee or make any changes in the applicable guarantee that would adversely affect such holder; or

change the requirements relating to waiving a default in payment of principal of, or premium, if any, or interest on, the debt securities of a series, the right to bring suit to enforce such payments or the provisions relating to modifications or amendments described in this sentence.

to evidence the succession of another person to such issuer pursuant to the provisions of the indenture relating to consolidations, mergers and sales of assets and the assumption by such successor of such issuer’s covenants, agreements and obligations in the indenture and with respect to the debt securities;

to surrender any right or power conferred upon such issuer, to add to the covenants such further covenants, restrictions, conditions or provisions for the protection of the holders of such series of debt securities, and to make the occurrence, or the occurrence and continuance, of a default in respect of any of such additional covenants, restrictions, conditions or provisions a default or an event of default under the indenture with respect to such series; provided, however, that with respect to any such additional covenant, restriction, condition or provision, such supplemental indenture may provide for a period of grace after default, which may be shorter or longer than that allowed in the case of other defaults, may provide for an immediate enforcement upon such default, may limit the remedies available to the trustee upon such default or may limit the right of holders of a majority in aggregate principal amount of any series of debt securities to waive such default;

to cure any ambiguity or correct or supplement any provision contained in the indenture, in any supplemental indenture, board resolution or officers’ certificate or in any debt securities that may be defective or inconsistent with any other provision contained therein;

to convey, transfer, assign, mortgage or pledge any property to or with the trustee, or to make such other provisions in regard to matters or questions arising under the indenture as shall not adversely affect the interests of any holders of debt securities of such series;

to modify or amend the indenture in such a manner as to permit the qualification of the indenture or any supplemental indenture under the Trust Indenture Act as then in effect;

to add to or change any of the provisions of the indenture to provide that debt securities in bearer form may be registrable as to principal, to change or eliminate any restrictions on the payment of principal, premium or interest with respect to debt securities in bearer form, to permit securities in registered form to be exchanged for securities in bearer form or to permit or facilitate the issuance of debt securities of such series in uncertificated form, provided that any such action shall not adversely affect the interests of the holders of debt securities or any coupons of any series in any material respect;

in the case of subordinated debt securities, to make any change in the provisions of the indenture or any supplemental indenture, board resolution or officers’ certificate relating to subordination that would limit or terminate the benefits available to any holder of senior indebtedness under such provisions, subject to any consent required under the terms of such senior indebtedness;

to add guarantees with respect to the debt securities or to secure the debt securities;

to make any change that does not adversely affect the rights of any holder of debt securities of such series;

to evidence and provide for the acceptance of appointment by a successor or separate trustee with respect to the debt securities of one or more series and to add to or change any of the provisions of the indenture as shall be necessary to provide for or facilitate the administration of the indenture by more than one trustee; or

to establish the form or terms of debt securities and coupons of any series, as described under “— General” above.

the title of such subscription rights;

the securities for which such subscription rights are exercisable;

the exercise price for such subscription rights;

the number of such subscription rights issued to each stockholder;

the extent to which such subscription rights are transferable;

the date on which the right to exercise such subscription rights shall commence, and the date on which such rights shall expire (subject to any extension);

the extent to which such subscription rights include an over-subscription privilege with respect to unsubscribed securities;

if applicable, the material terms of any standby underwriting or other purchase arrangement that we may enter into in connection with the subscription rights offering; and

any other terms of such subscription rights, including terms, procedures and limitations relating to the exchange and exercise of such subscription rights.