Can the Maestro Sport be used on an airplane, and are there any restrictions?

Yes, the Maestro Sport can be used on aircraft, but only with the 5-point harness — it cannot be used in booster mode on an aircraft. The FAA recommends using a forward-facing child restraint for children weighing 9 to 18 kg (20 to 40 lbs), and you should check with your airline before departure to ensure the restraint meets their requirements. (Page 17, 46–48)