BMW S38, an updated version of the BMW M88/3 engine
Short S.38, a name often applied to a Short Improved S.27 bearing Admiralty number 38, a British biplane which achieved a number of British and world naval aviation firsts in 1911-1912
Sikorsky S-38, a 1928 American twin-engined 8-seat amphibious aircraft
USS S-38 (SS-143), a 1919 S-class submarine of the United States Navy