Trans World Airlines Martin 404 1950 The Martin 4-0-4 was an American pressurized passenger airliner built by the Glenn L. Martin Company. In addition to airline use initially in the United States, it was used by the United States Coast Guard and United States Navy as the RM-1G First flight October 21, 1950 Introduction 1951 Primary users Eastern Air Lines, Trans World Airlines Produced 1951-1953 Number built 103 Only two left in the USA. Two flying in Venezuela.