Flown Rockwell International USAF postal cover with a ‘Guardian of the Peace’ cachet carried on the first flight of Rockwell’s B-1 bomber prototype, 6.5 x 3.75, canceled on the day of the flight, December 23, 1974. The cover also bears an affixed 10-cent Skylab postage stamp and typed address. In fine condition, with toning to edges.
