The first A-12, known as Article 121, was built and ground tested in Burbank during January and February 1962. Because the aircraft was too secret to fly to the test site and too large to carry on a cargo plane, it had to be trucked. 

Article 123 was lost on 24 May 1963 during a low-altitude, subsonic flight to test an inertial navigation system.

The only A-12 trainer (927) was a two seater version intended for pilot training. The A-12B trainer was known as The Titanium Goose.

With a faulty fuel gauge, CIA Pilot Walt Ray was on final to Groom Lake, NV, when the A-12 ran out of fuel. Walt Ray ejected from the aircraft, he failed to seperate from the ejection seat and was killed when he landed in seat.