His son, Holger, won a Kremer prize in the same year for his flight over a 1,500 m (4,900 ft) triangular course, improving the record to 4 minutes and 25 seconds.

In the same year, he set a world speed record at 35.7 km/h (22.2 mph), receiving a second Kremer prize.

Later that year, Holger and his sister Katrin, at that time still a child, became the first passengers in a human-powered aircraft.

[citation needed] Günther designed Musculair 2, and Holger slimmed down to just 41 kilograms (90 lb) to reduce the total mass of craft and human, leading to him setting a new Fédération Aéronautique Internationale world record for a human-powered aircraft at 44.32 kilometres per hour (27.54 mph) on 2 October 1985.

Musculair 2 is on display at the specialist Deutsches Museum Flugwerft Schleissheim in Oberschleißheim.