When a vehicle moves, it makes a path of air behind it. This path of air is called a slipstream.
Slipstreams are important in racing because they can help a vehicle go faster.
Examples:
The car drove through the slipstreams of the other cars.
The airplane flew in the slipstreams of the birds.
The slipstreams from the boat made the water move.
The slipstreams from the fan cooled us down.
The slipstreams of the rocket were very big and strong.
The slipstreams of the big truck made my kite fly higher.