MIDDLETOWN, Conn. (AP) — Pratt & Whitney is marking the final delivery of a military jet engine in what an executive calls a bittersweet event.

The subsidiary of United Technologies Corp. and representatives of the Air Force, Lockheed Martin and Boeing will mark the delivery Thursday of the 507th and last F-119 engine for the Air Force's F-22 Raptor at Pratt & Whitney's plant in Middletown.

Then-Defense Secretary Robert Gates announced the end of production in 2010. Pratt & Whitney delivered the first production F-119 engine in December 2000.

Bennett Croswell, president of military engines at Pratt & Whitney, says the company doesn't often see engines end production, making the ceremony an unusual event. He called it bittersweet.

In a partnership with the Air Force, Pratt & Whitney will shift to managing scheduled overhauls of the F119 engine fleet.