The force that opposes thrust in an airplane is called drag.

Here's why:

* Thrust is the forward force generated by the engines, pushing the airplane through the air.

* Drag is the resistance the airplane experiences as it moves through the air. This resistance comes from friction between the airplane's surfaces and the air, and from the way the air is pushed aside as the airplane moves.

Think of it like this: thrust is like the engine pushing you forward in a car, while drag is like the wind pushing back against you.