ADAC Formula 4 Championship In
2015, Fittje made his single-seater debut in the
ADAC F4 championship with
Team Motopark. He finished the season 18th with 22 points. In 2016, Fittje got on the podium for the first time in his single seater career where he finished 3rd at
Oschersleben. He had two more podiums that season, finishing the season seventh with 133 points.
GP3 In
2018, Fittje replaced
David Beckmann at
Jenzer for the final five races of the
GP3 Season. Fittje finished the season with no points and his highest finished was tenth at
Sochi.
Porsche Supercup Fittje competed one race in the
2019 Porsche Mobil 1 Supercup for
Team Project 1 - Fach in
Spain where he recorded one point by finishing 16th.
GT World Challenge For the 2022 season, Fittje joined Haupt Racing Team to compete in the Silver Cup of the
GT World Challenge Europe Endurance Cup alongside
Jordan Love and Alain Valente. The team failed to score any points in the main championship whilst taking tenth place in the category standings. During 2023, Fittje teamed up with Antares Au,
Matteo Cairoli and
Tim Heinemann in the Bronze Cup for the
24 Hours of Spa. This would prove to be a resounding success as Fittje, having seen Cairoli take overall pole position, helped his outfit to a class victory, which he later called "the biggest and best result" of his career. ==Racing record==