BK-1, the United Kingdom's first Lockheed Martin F-35 Lightning II production aircraft, flew its inaugural flight Friday.

Lockheed Martin test pilot Bill Gigliotti took the short takeoff/vertical landing (STOVL) jet through a series of functional flight checks during a sortie that lasted 45 minutes.

The jet will complete a series of company and government checkout flights prior to its acceptance by the U.K. Ministry of Defence.

The U.K. MOD will use this 5th Generation fighter for training and operational tests at Eglin Air Force Base, Fla., beginning later this year.

"Not only is this a watershed moment for the Joint Strike Fighter program, since BK-1 is the first international F-35 to fly, but it also brings us one step closer to delivery of this essential 5th Generation capability for the U.K., " said Group Captain Harv Smyth, the Joint Strike Fighter U.K. National Deputy.