[backwoods-engineer]

couldn’t the energy produced by spinning wheels be harnessed somehow to compress air real-time onboard?

That would be known as a Type 1 Perpetual Motion Machine. Do you have one that works? I'll give you a million dollars right now if it is demonstrated to work for a week under load.

[Squawk 8888]

Not perpetual motion, but regenerative braking. A compressor linked to the wheels would capture the energy and use it to accelerate, which could substantially reduce fuel consumption.