Can't realistically fly with a 30. Steel 15 vs AL 19 vs Steel 23 (basically a longer narrower 19 if I can't get 3442 fills). Maybe Steel 15 which would be a 13 if I couldn't get full 3442 fills.
This is because doing solo cert/diving, need a second source and given that carrying own big bottle is going to be a no-go ....
Anticipate most all my diving will be in the Caribbean reached mainly via Continental Airlines (even if they do business under the "Uni-Ted name) or Southwest. Or if there absolutely, positively is no other choice, American (I drive past their big DFW hub to get to Southwest at Dallas). Only very rarely will I be dive traveling via Subaroo.
But since you won't be using your 30 anymore, it will need a new home to feel wanted and included. Tell me more about it. Is it housebroken?
OMMOHY
Oh, dear. The trials and tribulations of vacation divers.