TransDigm Group INC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

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Securities Exchange Act of 1934

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Message from Our CEO

Dear Fellow Stockholders,It is a privilege to write to you ahead of my first Annual Meeting as TransDigm’s Chief Executive Officer (“CEO”). On behalf of our Board of Directors, I want to thank you for your continued investment in TransDigm. We value your support as we continue to seek long-term, “private equity-like” returns through acquiring, owning, and operating proprietary aerospace businesses with significant aftermarket content. Our continued execution of our value-based operating methodology enabled us to deliver strong financial results in FY 2025.

2025 Business PerformanceWe continued to achieve steady, long-term growth in sales and improvements in operating performance in FY 2025, setting a solid foundation for FY 2026. In FY 2025, we generated net sales of $8.8 billion and EBITDA As Defined of $4.8 billion, representing 11% and 14% growth, respectively. Additionally, during our FY 2025 and continuing into early October 2025, we deployed approximately $0.9 billion of capital, as we acquired two proprietary aerospace businesses - Servotronics and Simmonds Precision Products. In addition to deploying capital for accretive acquisitions in FY 2025, we returned significant value to our stockholders through two special dividends - $75.00 per share in October 2024 and $90.00 per share in September 2025 - for a total of approximately $9.6 billion. We also allocated capital for $500 million of share repurchases throughout FY 2025. We are continuously assessing our capital allocation opportunities, and we were very pleased to return this capital to our shareholders.Strategic Leadership TransitionsI assumed the role of President and CEO on October 1, 2025, succeeding Kevin Stein and marking a key milestone in our leadership evolution. This was a thoughtful and well-planned succession, and Kevin and I have worked closely to ensure a smooth transition for our stakeholders. He will remain an advisor to TransDigm to aide in any transition topics through fiscal 2027. Kevin served TransDigm with dedication for more than a decade, and I want to thank him on behalf of the whole company for his vision and steady stewardship. In further bolstering our operational leadership and in alignment with our robust succession planning, we appointed Patrick Murphy as Co-Chief Operating Officer in August 2025. Patrick brings deep operational expertise, having most recently served as a TransDigm Executive Vice President with direct oversight of several operating units. Patrick now works alongside Joel Reiss, TransDigm’s other Co-Chief Operating Officer, to drive value creation across our operating units. An Engaged and Fit-for-Purpose BoardOur Board has also seen several transitions in the past year. In October 2025, I joined the Board of Directors in connection with my promotion to CEO. The Board also appointed Pete Palmer, a former TransDigm Executive Vice President, as a Director. Pete’s appointment strengthens the Board’s operational expertise and institutional knowledge of TransDigm’s operations. I am happy to welcome Pete to the TransDigm Board and look forward to working with him again in our new roles. As we embark on FY 2026, our priorities remain clear: drive operational excellence, thoughtfully allocate capital, and deepen value creation in every area of our business. We remain committed to our operating methodology, key value drivers, effective cost management, and disciplined acquisition strategy. I remain confident in our strategy, our people, and our long-term mission. On behalf of the management team, I thank you for your continued trust and support and look forward to working together to continue creating value for our stockholders in FY 2026.Sincerely,Michael J. LismanPresident and Chief Executive Officer

Message from the Lead Independent Director

Dear Fellow Stockholders,This past year has been both productive and transformative for the Board. We oversaw the deployment of significant capital, including two acquisitions; important leadership transitions, most notably within our CEO role; and several changes to the composition of the Board itself.Following a thoughtful succession process, the Board announced in May 2025 that Mike Lisman, our co–Chief Operating Officer, would succeed Kevin Stein as CEO at the end of fiscal year 2025. Following the transition on October 1, 2025, Kevin remains in an advisory role, through fiscal 2027, to support a seamless transition. The Board is deeply grateful for Kevin’s leadership and longstanding service to TransDigm, and we look forward to working closely with Mike as he leads the organization into its next chapter.

We also oversaw meaningful Board changes this year. In July 2025, Jorge Valladares resigned from the Board due to new professional obligations at another organization. We appreciate Jorge’s contributions and the valuable industry and operational expertise he brought to the Board. In October 2025, we welcomed two new directors: Mike Lisman, who joined the Board in connection with his promotion to CEO, and Pete Palmer, a former TransDigm Executive Vice President. Pete brings significant industry, operational, leadership, and M&A experience—capabilities that will enhance the Board’s oversight and accountability of vital operational priorities. Throughout this year, we continued our regular engagement with shareholders, discussing topics such as corporate strategy, governance practices, Board composition, and executive compensation. On behalf of the entire Board, thank you for your perspectives and thoughtful feedback. We deeply value your engagement and remain committed to strengthening the dialogue between the Board and our stockholders.It has been a rewarding year for me as Lead Independent Director and an exciting period for TransDigm as we maintain our focus on operational excellence and disciplined, strategic growth. I look forward to continuing this progress together.Thank you for choosing to invest in TransDigm. Sincerely,Robert J. SmallLead Independent Director

Special Note Regarding Forward-Looking Statements

These proxy materials contain forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and Section 27A of the Securities Act of 1933, as amended.

These forward-looking statements are subject to risks, uncertainties and other factors and actual results may differ materially from any results projected in the statements. These risks, uncertainties and other factors include, without limitation: but are not limited to: the sensitivity of our business to the number of flight hours that our customers’ planes spend aloft and our customers’ profitability, both of which are affected by general economic conditions; supply chain constraints; increases in raw material costs, taxes and labor costs that cannot be recovered in product pricing; failure to complete or successfully integrate acquisitions; our indebtedness; current and future geopolitical or other worldwide events, including, without limitation, wars or conflicts and public health crises; cybersecurity threats; risks related to the transition or physical impacts of climate change and other natural disasters or meeting regulatory requirements; our reliance on certain customers; the United States defense budget and risks associated with being a government supplier including government audits and investigations; failure to maintain government or industry approvals; risks related to changes in laws and regulations, including increases in compliance costs and potential changes in trade policies and tariffs; potential environmental liabilities; liabilities arising in connection with litigation; risks and costs associated with our international sales and operations; and other factors. Further information regarding the important factors that could cause actual results to differ materially from projected results can be found in TransDigm Group’s most recent Annual Report on Form 10-K (“2025 Form 10-K”) and other reports that TransDigm Group or its subsidiaries have filed with the Securities and Exchange Commission (“SEC”). Except as required by law, TransDigm Group undertakes no obligation to revise or update the forward-looking statements contained in this proxy statement.

Notice of the Annual Meeting

of Stockholders to be held March 5, 2026

Notice is hereby given that the annual meeting of stockholders (“annual meeting”) of TransDigm Group Incorporated, a Delaware corporation, will be held at 1350 Euclid Avenue, Suite 1600, Cleveland, Ohio 44115, on Thursday, March 5, 2026, at 9:00 a.m., Eastern time, for the following purposes:

Only stockholders of record at the close of business on January 9, 2026 will be entitled to notice of and to vote at the annual meeting or any adjournment of the annual meeting.

Your vote is important. Whether or not you plan to attend the annual meeting, please vote on the internet, by phone, or by completing and returning the enclosed proxy card.

By order of the Board of Directors,

Armani Vadiee

General Counsel, Chief Compliance Officer & Secretary

January 23, 2026

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON MARCH 5, 2026.The Proxy Statement and Proxy Card are available at http://www.transdigm.com/investor-relations/annual-proxy

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