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 (Amendment No. )

AAR CORP.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Dear fellow stockholders:

AAR began the fiscal year ended May 31, 2024 (“Fiscal 2024”) on course for continued value creation, and I am pleased to report that we delivered.

Demand for air travel was strong throughout the year. This demand was supported by an increase in the utilization of existing aircraft, which drove even greater requirements for aftermarket parts and maintenance. Our strategic focus was well timed, and we were able to leverage the depth and breadth of our capabilities to deliver exceptional services to our customers.

In March 2024, we further enhanced our offerings by acquiring Triumph Group’s Product Support business, meaningfully scaling AAR’s Component Services through additional complementary services, proprietary capabilities, and a footprint in the fast-growth Asia-Pacific region. This acquisition makes us a leader in component repair, complementing our leading positions in parts supply and airframe maintenance.

In addition to our acquisition of Triumph Product Support, we began to see the benefits of AAR’s March 2023 acquisition of Trax. Customers demonstrated a high level of interest in Trax’s eMRO aviation software and eMobility applications, and we believe AAR’s relationships expedited business wins. Further, Trax’s leading aircraft maintenance management software provides additional differentiated offerings for our customers.

AAR’s growth strategy has long included both inorganic and organic growth. In addition to the Triumph and Trax acquisitions, we are expanding organically as well. Thanks to the continued trust of our long-term customers, we recently broke ground on additional hangars in Miami and Oklahoma City, which we expect to complete next year.

We welcomed Jeffrey Edwards and Billy Nolen to AAR’s Board of Directors in Fiscal 2024, bringing additional financial and safety expertise to our Board, respectively. I continued to be grateful to our Board for their support and guidance. On that note, on behalf of the entire AAR family,

I wish to thank Anthony K. Anderson, who will retire from the Board at our 2024 annual meeting, for 12 years of distinguished service on our Board of Directors. AAR remains steadfast in our commitment to quality and safety. We proudly advocate for industry-wide safety goals, drive innovation with customers, and create opportunities to cohesively advance safety in the industry. As we embark on our 2025 fiscal year and our 70th year of operations, we will continue reaching higher for our valued team members, customers, partners, and shareholders.

With that, I am pleased to invite you to AAR’s 2024 annual meeting of stockholders, which will be a virtual meeting. The annual meeting will be held on Tuesday, September 17, 2024, 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/AIR2024 and entering your control number.You will not be able to attend the annual meeting in person.

I encourage you to read our 2024 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 meeting.

We are grateful to our employees for their hard work and commitment, and to you, our stockholders, for choosing to invest in AAR.

Sincerely,

John M. Holmes

Chairman, President and Chief Executive Officer

Notice of 2024 annual meeting of stockholders

To our stockholders:

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 2024 annual meeting.

By Order of the Board,

**Jessica A. Garascia

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

August 6, 2024

2