Well, You have 2.5 years to crate train him if that is your wish. You also have time to ask about and possibly even trial run tranquilizers (speak to the vet).

To crate train, keep a cage or carrier in your home and set up ALL the time. Feed him in there. Start with the door open. Then begin very slowly closing him in there for short periods of time which will get longer and longer. Take him for car rides (If that is possible) to get used to the movement.
As far as no food or litter in the carrier, resist the urge to feed him right before takeoff. Let his tummy be empty for an hour or 2 (ask a vet for a more accurate amount of time) before the trip. Hopefully he will use the box before the time of the flight and less food in tummy equals less chance of nausia. It is NOT cruel, because cats going under surgery cannot have food for for 12 hours before surgery and then they will not be fed for another 12 to 24 hours after surgery to prevent nausia from the anestesia, so Boomer will be fine (Food wise).

If your crate training efforts fail after you give him a reasonable amount of time you will still have time to think about the re-homing route.

JMO