Last time at WDW & DL I saw people on the plane with their carrying case, no issues getting on the plan as they are narrow and fit in bins above easily. I think shipping is an option as well.
Sadly, the technology doesn't currently exist to create a real lightsaber. However, you can pack a toy lightsaber in your carry-on or checked bag. May the force be with you.
We just got back. We flew jetblue and the two people who had window seats just put the lightsabers next to them on the window side. We were afraid to put them in the overhead bin.
We flew back with the Savi ones in the overhead bin no problem. But when we got the dark Saber which was fully packed in a box, that we had the hotel ship it back for us and that worked great too.