Reg FD Disclosure · Company Update

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549   FORM  8-K   CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934   Date of Report (Date of Earliest Event Reported): December 17, 2025   AAR CORP. (Exact name of registrant as specified in its charter)   Delaware   1-6263   36-2334820 (State of Incorporation )   (Commission File Number)   (IRS Employer Identification No.)   One AAR Place 1100 N. Wood Dale Road Wood Dale , Illinois 60191 (Address and Zip Code of Principal Executive Offices)   Registrant’s telephone number, including area code: ( 630 ) 227-2000   Not Applicable (Former name or former address, if changed since last report)   Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:   ¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))   Securities registered pursuant to Section 12(b) of the Act:   Title of Each Class   Trading Symbol(s)   Name of Each Exchange on Which Registered Common Stock, $1.00 par value   AIR   New York Stock Exchange     NYSE Texas   Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b—2 of this chapter).   Emerging growth company  ¨   If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ¨           Item 7.01.  Regulation FD Disclosure.   On December 17, 2025, AAR CORP. (the “Company”) issued a press release announcing the entry into a definitive agreement by its wholly-owned subsidiary AAR Aircraft Services, Inc. to purchase Aircraft Reconfig Technologies LLC, a leading aircraft interiors engineering company, from ZIM Aircraft Cabin Solutions LLC. A copy of the press release is furnished and attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.   The information in this Item 7.01 and Exhibit 99.1 attached hereto shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, nor shall it be deemed incorporated by reference in any filing under the Securities Act, except as shall be expressly set forth by specific reference in such filing.   Item 8.01.  Other Events.   On December 17, 2025, AAR Aircraft Services, Inc., a wholly-owned subsidiary of the Company, entered into a definitive agreement to acquire Aircraft Reconfig Technologies LLC for a purchase price of $35 million in cash, subject to customary post-closing adjustments for working capital, cash, and debt.   Item 9.01.  Financial Statements and Exhibits.   (d) Exhibits   Exhibit No.   Description 99.1   Press release issued by AAR CORP. on December 17, 2025 104   Cover Page Interactive Data File (the cover page XBRL tags are embedded in the Inline XBRL document)      SIGNATURE   Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.   Date: December 17, 2025     AAR CORP.       By: /s/ Jessica A. Garascia     Jessica A. Garascia     Senior Vice President, General Counsel, Chief Administrative Officer and Secretary