Hi Rick! I've been binding with GC2B binders for the last few months, and they're really great. I can wear them for 12+ hours without a problem, and I can move and breathe easily in them. Underworks are also good, but not quite as comfortable.
The other thing is that since flights in general aren't a comfortable thing in the first place, maybe try layering two sports bras instead? They would be a bit more comfortable than binding, given the length of your travel day. You could also change out of your binder into a sports bra at some point during the day if it's too much. Hope you enjoy your trip!