Bensen used to do what they called a "GyroGlider" I think, which was indeed towed to launch.
IIRC it was meant to remain tethered as you got towed down a runway or similar (only seen ones with wheels before) and I believe was meant as a trainer before you were let loose on the powerd version. Seem to recall seeing fillums of it in me youth .....
[edited to add]
..found a picture ... ain't Google wonderful
