WW I flying ace; an active champion for a strong independent air force, he was court-martialed for insubordination and suspended from duty for five years in 1925. TLS signed “Wm. Mitchell,” one page, 7.25 x 10.5, personal letterhead, May 11, 1931. Letter to H. H. Haeberly regarding an upcoming visit. In part, “I thoroughly intend coming up to see the autogyro this week but I heard that you were away. I not only wanted to see the autogyro but thought it might be possible to fly it up to the Army airplane maneuvers which are to be held in New York.” In fine condition, with staple holes and creases to top left, and a mailing fold affecting the tops of a couple letters of signature. R&R COA.