First flight air mail cover addressed to William E. Boeing, Seattle, Washington, from the Glenn L. Martin Company, Baltimore, Maryland, July 3, 1942.Stamped cachet: "First Flight - This cover carried on first official flight of the 'Mars,' built by…
Commemorative letter honoring the 25th anniversary of Glenn L. Martin's record-making flight from Newport Bay, California to Avalon, Catalina Island, then the longest over-water flight in aviation history, May 10, 1937. One typed page on Glenn L.…