In the US, scooters can be gate-checked, and this is what I would recommend that you do. When you get to your gate, ask for a gate check tag for your scooter. You will be boarded first. Remove the key to your scooter and anything else (cushion, basket, etc) that can be removed. Make sure that you have some sort of securely fastened tag on the scooter with your name and contact information.
On arrival, the scooter will be brought planeside for you.