ASTRONICS CORP

The Company issued the Notes pursuant to an indenture (the “Indenture”), dated as of September 16, 2025, between the Company and U.S. Bank Trust Company, National Association, as trustee (the “Trustee”).

The Notes will mature on January 15, 2031, unless earlier converted, redeemed or repurchased. The Notes will not bear regular interest, and the principal amount of the Notes will not accrete. The Notes are the Company’s senior unsecured obligations and are (i) equal in right of payment with the Company’s existing and future senior unsecured indebtedness; (ii) senior in right of payment to the Company’s existing and future indebtedness that is expressly subordinated to the Notes; (iii) effectively subordinated to the Company’s existing and future secured indebtedness, to the extent of the value of the collateral securing that indebtedness; and (iv) structurally subordinated to all existing and future indebtedness and other liabilities, including trade payables, of the Company’s subsidiaries.

Prior to the close of business on the business day immediately preceding October 15, 2030, noteholders will have the right to convert their Notes only upon the occurrence of certain events. On or after October 15, 2030, noteholders may convert all or any portion of their Notes at any time at their election until the close of business on the second scheduled trading day immediately preceding the maturity date. Upon conversion, the Company will satisfy its conversion obligations by paying cash up to the aggregate principal amount of the Notes to be converted and paying and/or delivering, as the case may be, cash, shares of its common stock or a combination of cash and shares of its common stock, at its election, in respect of the remainder, if any, of its conversion obligation in excess of the aggregate principal amount of the Notes being converted. The initial conversion rate for the Notes is 18.2243 shares of common stock per $1,000 principal amount of Notes (equivalent to an initial conversion price of approximately $54.8718 per share of common stock), which represents an approximately 25% conversion premium over the reference price of $43.8974 per share of the Company’s common stock, which was the volume-weighted average price of the Company’s common stock on September 10, 2025 (the “Reference Price”). The conversion rate (and accordingly the conversion price) is subject to adjustment upon the occurrence of certain events. In addition, upon certain corporate events or upon a notice of redemption (as described below), the Company will, under certain circumstances, increase the conversion rate for noteholders who convert Notes in connection with such a corporate event or convert their Notes called (or deemed called) for redemption during the related redemption period, as the case may be.

The Notes will not be redeemable before January 22, 2029. The Notes will be redeemable, in whole or in part, for cash at the Company’s option at any time, and from time to time, on or after January 22, 2029 and prior to the 51st scheduled trading day immediately preceding the maturity date, if (1) the Notes are “freely tradable” (as defined in the Indenture), and certain accrued and unpaid Special Interest (as defined in the Indenture), if any, has been paid in full, as of the first Special Interest payment date occurring on or before the date the Company sends such notice and (2) the last reported sale price per share of the Company’s common stock has been at least 130% of the conversion price for a specified period of time. The redemption price will be equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid Special Interest, if any, to, but excluding, the redemption date.

If a Fundamental Change (as defined in the Indenture) occurs, then, subject to limited exceptions, noteholders may require the Company to repurchase their Notes for cash. The repurchase price will be equal to the principal amount of the Notes to be repurchased, plus accrued and unpaid Special Interest, if any, to, but excluding, the applicable repurchase date. The definition of Fundamental Change includes certain business combination transactions involving the Company and certain de-listing events with respect to the common stock.

The Indenture contains customary provisions relating to the occurrence of “Events of Default” (as defined in the Indenture), which include the following: (i) certain payment defaults on the Notes (which, in the case of a default in the payment of Special Interest on the Notes, will be subject to a 30-day cure period); (ii) the Company’s failure to send certain notices under the Indenture within specified periods of time; (iii) the Company’s failure to comply with certain covenants in the Indenture relating to the Company’s ability to consolidate with, merge with or into, or sell, convey, transfer or lease all or substantially all of the consolidated properties and assets of the Company and its subsidiaries, taken as a whole, to another person; (iv) a default by the Company in its other agreements under the Indenture or the Notes if such default is not cured or waived within 60 days after notice is given in accordance with the Indenture; (v) certain defaults by the Company or any of its significant subsidiaries with respect to indebtedness for money borrowed in excess of $20,000,000; (vi) the failure of the Company or any of its significant subsidiaries to pay a final judgment or judgments in excess of $20,000,000 within certain specified time periods; and (vii) certain events of bankruptcy, insolvency and reorganization involving the Company or any of its significant subsidiaries.

If an Event of Default involving bankruptcy, insolvency or reorganization with respect to the Company (and not solely with respect to a significant subsidiary of the Company) occurs, then the principal amount of, and accrued and unpaid Special Interest, if any, on, all of the Notes then outstanding will immediately become due and payable without any further action or notice by any person. If any other Event of Default occurs and is continuing, then, the Trustee, by notice to the Company, or noteholders of at least 25% aggregate principal amount of the Notes then outstanding, by notice to the Company and the Trustee, may declare 100% of the principal of, and accrued and unpaid Special Interest, if any, on all of the Notes then outstanding to become due and payable immediately. However, notwithstanding the foregoing, the Company may elect, at its option, that the sole remedy for an Event of Default relating to certain failures by the Company to comply with certain reporting covenants in the Indenture consists exclusively of the right of the noteholders to receive Special Interest on the Notes during the first 180 days after the occurrence of such Event of Default at a rate per annum equal to 0.25% on the principal amount of the Notes and, thereafter, at a rate per annum equal to 0.50% on the principal amount of the Notes.

The above description of the Indenture and the Notes is a summary and is not complete. A copy of the Indenture and the form of the Notes are filed as exhibits 4.1 and 4.2, respectively, to this Current Report on Form 8-K, and the above summary is qualified by reference to the terms of the Indenture and the Notes set forth in such exhibits.