What happens if you have the card equipped, but have no legal pre-move for the ship without bumping?

You still activate the card, and move as if you normally would, bump, and then execute your maneuver. It does not follow the rule of boosting/barrel rolling that requires you to complete it without bumping

Adaptive Ailerons specifies that you're performing a maneuver, so you follow all the rules for performing a maneuver.