[1] Where is the code that controls a unit's speed [ how fast it moves on land or air ] ?
I can't find anything in the code for this except for tire rotation.
And the animation would look dumb because you could only have it roll in one direction. So there would be instances where the plane would roll to the right and turn to the left simultaneously.
Afterburners is done with a locomotor upgrade that creates a new conditionstate that has a bigger particle effect for the engines.