F/Lt. J. Flinterman was a 20 year-old officer in the Dutch Air Force when the Germans invaded Holland in 1940, but he managed to escape to England where he joined the Royal Air Force.
Jan trained as a Spitfire pilot and flew with 126 Squadron in Malta, earning the nickname "Crazy Flinn" for his exploits. When Holland's Prince Bernhard, a German who had married into the Dutch royal family, convinced the British to start a Dutch squadron, Flinterman was one of the pilots to join the new 322 (Dutch) Squadron in the summer of 1943.

In May 1944, Jan transfered to 222 Squadron as a Flight Lieutenant and was awarded the Distinguished Flying Cross after a huge dogfight over Paris. By the end of the war he had also been awarded Holland's Order of Orange-Nassau and the Vliegerkruis (Flying Cross).

After the war he switched to flying Meteors jets before he left the RAF to take up the post of head of Holland’s fighter pilot school with the rank of Major.
Jan Flinterman died in Leiden in Holland in 1992 at the age of 73.

Jan Flinterman was also a keen driver and started racing in 1950 with a Cooper-BSA Formula 3 car. In 1952 he became the first Dutchman to contest a Grand Prix, driving an Escuderia Baneirantes Maserati A6GCM in the Dutch Grand Prix. His car retired with a broken differential whereupon he took over Chico Landi’s car to finished ninth, seven laps down on the winner Alberto Ascari.