slipstream

Concise Oxford English Dictionary © 2008 Oxford University Press:
slipstream/ˈslɪpstriːm/

▶noun

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

  ■ the partial vacuum created in the wake of a moving vehicle.

• 2 an assisting force regarded as drawing something along in its wake.

▶verb follow in the slipstream of a vehicle, especially when awaiting an opportunity to overtake in motor racing.