3-5/8x6.5" envelope postmarked April 3, 1938 in Boulder City, Nev. Has large stamp of plane and has "Boulder City, Nevada First Flight United States Air Mail." Line provided for sender address has blue fountain pen signature of Charles A. Lindbergh. Appropriately enough, this flight first is signed by one of the pioneers of flight. Envelope has usual red/blue ticks to margins indicating air mail and a cancelled 6¢ air mail stamp. Addressed but does not appear to have been sealed and envelope is empty. Front has lt. aging on left side but this does not affect signature. 1/16" tear at bottom right margin, not noticeable unless under close inspection. Overall VF to Exc. w/Exc. signature. Comes w/letter of authenticity from Hake's.