Youngest B-52 celebrates 50 years with the US Air Force Friday marks the 50th anniversary of the last B-52 delivered to the U.S. Air Force. Tail No. 61-040 was assigned to Minot Air Force Base, N.D., in 1962. Over the past 50 years, the airplane has had many assignments, but today it is back at Minot with the 5th Bomb Wing. There are 76 B-52 H models in service today, and all were built in Wichita, Kan. Last month, the Wichita site celebrated this golden milestone for Tail No. 1040.