Can an engine run on air? I think it can, but I am not sure

Hello,

NO, and engine can run on steam, gas and other things but not air.

-Bella

Unfortunately, air alone can't be used as a fuel.

First, energy has to be stored in it by squeezing the air tightly using a mechanical air compressor.

Once the compressed air is released, it expands. This expanding air can be used, for example, to drive the pistons that power an engine.