Renner joined Bill Riley's[3] Sportavia Soaring Centre, a commercial gliding operation in Tocumwal (NSW), as flight instructor shortly after moving to Australia.

[4] From 1974, he worked during the European summers as a flight instructor at the Oerlinghausen training centre and at its branches in southern Europe, such as at Sondrio.

[1] In 2006, Sportavia Soaring Centre closed but the Murray Border Flying Club extended its operations to include gliding.

Renner is reported to have utilized the dynamic soaring technique with a Glasflügel H-301 Libelle at Tocumwal in 1974 and later flights in an Eiri-Avion PIK-20.

In 1975, he and Hilmer Geissler flew a two-seat glider (Caproni Vizzola Calif A-21) a straight distance of 970.4 kilometres (603.0 mi) from Bendigo in Victoria to Langley, a location approximately 120 kilometres (75 mi) west of Bundaberg in Queensland.