AAR CORP

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE

SECURITIES EXCHANGE ACT OF 1934

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AAR CORP.

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Dear fellow stockholders,

Fiscal Year 2026 was a year of significant progress for AAR. We set a series of financial records, completed four acquisitions, progressed and completed facility expansions, launched innovative new software products, and further defined our strategy focusing on Parts, Repair, and Software.

The energy across AAR's global operations fueled a year of strong execution. We delivered the high standards our commercial and government customers expect with the urgency required to keep aircraft flying. The pace of that execution reinforced a defining aspect of how we operate, leading us to add nonstop to our longstanding brand promise, now Doing it right. Nonstop. TM

AAR’s repositioned portfolio and focused strategy drove record-breaking financial results in Fiscal Year 2026. Powered by our Parts, Repair, and Software platform, we delivered industry leading turnaround times at our Airframe MRO facilities, realized significant market share gains for our new parts Distribution customers, and fully embraced AI in our software offering. The strength of our execution translated into the highest revenue, profitability, and earnings in AAR’s history.

Nothing is more important than safety, a principle deeply embedded in AAR's culture. During Fiscal Year 2026, we expanded our Safety Management System (SMS) to our newly acquired repair facilities, implementing AAR's approach to safety across our growing repair network. We also conducted an anonymous safety culture survey that achieved 93% participation, with results significantly exceeding industry benchmarks across key measures of safety culture.

I continue to be grateful to our Board for their support and guidance. On that note, on behalf of all of us at AAR, I would like to thank General Duncan J. McNabb, who will retire from the Board at our 2026 annual meeting of stockholders, for his distinguished service as a director and as Chair of the Board’s Aviation Safety and Training Committee. Throughout his tenure, General McNabb has made a lasting impact on AAR’s safety culture and helped reinforce our “Quality first. Safety always.” value.

With that, I am pleased to invite you to AAR’s 2026 annual meeting of stockholders, which will be a virtual meeting. The annual meeting will be held on Wednesday, September 23, 2026, at 9:00 a.m., Central Time and you will be able to attend the annual meeting online, vote your shares electronically, and submit your questions during the annual meeting by visitingwww.virtualshareholdermeeting.com/AIR2026 and entering your control number. You will not be able to attend the annual meeting in person.

I encourage you to read our 2026 proxy statement, our annual report, and our other proxy materials. Please see Appendix B for reconciliations of non-GAAP financial measures. Whether or not you plan to attend the annual meeting of stockholders, your vote is important. Please follow the voting instructions to ensure that your shares are represented and voted at the annual meeting.

Thank you for your continued trust, confidence and investment in AAR.

John M. Holmes

Chairman, President and Chief Executive Officer

2026 Proxy Statement | 1

Notice of 2026 annual meeting

of stockholders

To our stockholders:

We are pleased to invite you to attend our 2026 annual meeting of stockholders (the “annual meeting”). Please read the information in this notice and proxy statement to learn more about AAR and the matters to be voted on at the annual meeting.

Items of business

You will be asked at our annual meeting to:

Stockholders will transact any other business that may properly come before the annual meeting or any adjournment or postponement of the annual meeting.

Voting

Your vote is important. We encourage you to vote your shares as soon as possible. You may vote by proxy over the Internet, by telephone, or by completing and returning the enclosed proxy card in the postage-paid envelope provided. If you are a “street name” stockholder (meaning that your shares are registered in the name of your bank or broker), you will receive instructions from your bank, broker or other nominee describing how to vote your shares. We also welcome you to attend the virtual meeting and vote online.

Please see Appendix A for important information about voting your shares at our 2026 annual meeting.

By Order of the Board,

Jessica Garascia

Senior Vice President, General Counsel, Chief Administrative Officer, and Secretary

August 4, 2026

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