Hamilton shipped out to England in late 1917 where he trained in early 1918 in an
Avro 504, perhaps at RFC
Bramham Moor which was then renamed RAF Tadcaster, near
Bramham cum Oglethorpe in Yorkshire. He first scored as a combat pilot on 11 April 1918, flying the
Sopwith Camel against his first German opponent, an
LVG C.VI observation aircraft. The next day he made his second aerial kill; his third a week later. On 20 April he was flying at the tail end of 'C' flight when his commander
Richard Raymond-Barker was attacked and killed by
Manfred von Richthofen, known as the Red Baron. From far away Hamilton saw Richthofen shoot down a second aviator (who crashed but lived), then Hamilton was near enough to engage a blue
Fokker Dr.I triplane, expending more than 300 rounds at it after which it went into a dive and spin, but Hamilton's own maneuvers prevented him from seeing what happened to it. Hamilton returned to base and claimed a kill but it was never confirmed—all of Richthofen's flight had returned safe from the engagement. On 3 June 1918, Hamilton became an ace, scoring his fifth confirmed victory. Hamilton was assigned to the USAS
17th Aero Squadron to help them complete their training. When they moved into combat, he was one of their
Flight Commanders. In his service he downed three enemy aircraft and two
observation balloons, becoming a double ace—once flying under RFC command and once again for USAS. His first USAS victory on 7 August was during an offensive patrol; the squadron was flying high at when they noticed eight
Fokker D.VIIs well below them over
Armentières. The 17th squadron dove to attack and Hamilton downed an enemy aircraft after firing 200 rounds. On Hamilton's final mission he was paired with Lt. Jesse F. Campbell to bomb and strafe transports along the Bapaume–Cambrai road, to strafe enemy troops in retreat and to attack an observation balloon that had been spotted to the north. After dropping their bombs on a small building and transports, Campbell and Hamilton turned to
bust the balloon. Hamilton sprayed the balloon with machine gun rounds, and its German observer officer was seen to jump from the basket as the balloon exploded in flame. Hamilton was then killed by defensive fire from ground forces. ==Legacy==