Flying and band issues, while rare, it's not too uncommon.
What one needs to remember, the plane is pressurized. This can have an affect on the human body (example, ears clog).
Since your insides have 'fluids', the change in pressure could affect internal pressure changes; especially on the stomach - hence your band could be affected.
Usually it's a minor discomfort, and everything is fine once on the ground.
However if you're really concerned, you may want to ask your Doctor to loosen the band until you come back.
Good Luck on your Journey !!
Tom
“Nothing I will ever eat will give me the feeling I get as when I lose weight” The views expressed are based on my own experiences - and should NOT BE FOLLOWED IN LIEU OF DOCTOR’S ADVICE/INSTRUCTIONS. Only your Doctor knows your condition, and make sure you talk to them before making any changes to your diet