Films

The Spindizzy
In James Blish's Cities In Flight, Volume I, They Shall Have Stars, an anti-gravity device, the Dillon-Waggoner graviton polarity generator, nicknamed the "spindizzy," is invented;

in Volume II, A Life For The Stars, spindizzies are used to fly cities between stars faster than light;

in Volume III, Earthman, Come Home, they also fly a planet between galaxies and two cities to the Greater Magellanic Cloud;

in Volume IV, The Triumph Of Time, they fly a planet not only between galaxies but also to the Metagalactic Centre.

The Haertel Overdrive
In Blish's Welcome To Mars, Adolph Haertel discovers anti-gravity and flies a tree hut to Mars;

in "Common Time" and later works, the Haertel overdrive flies spacecraft between stars faster than light.

Thus, the spindizzy and the Haertel overdrive are alternative interstellar drives.

Film Ideas
Proposed films based on Blish's works were:

Welcome To Mars;
A Life For The Stars;
The Space Witch, an original flying cities film for which Blish wrote a plot outline.

One way to tie these films together would have been to rename the spindizzy as the "Haertel graviton polarity generator."