Slipstream

[Vania]

The area behind a vehicle moving through something where there is not so much [air resistance] (if moving through air. This can be used to gain speed before overtaking someone in a race.
Also if in space when [your spaceship] is in the slipstream of another it cant be detected by the other [ships] sensors (but this is only if you are in an episode of star trek).

[Tanya Shivari]

A current of air or water driven back by a revolving propeller or jet engine.

[Greta]

Slipstream in IndyCars. The area of clean air behind a car that is generated by the wings and ground effect. This can be used to advantage by pursuing cars.