I have 3 SKB cases, I switched the lockable latches so 1 has 3 the others don't.

I wasn't really concerned for security cause TSA can open those but I was more concern with the other ones accidentally poping open. Id put some bubble wrap in the empty parts of the cases to make sure it can't slide around.
Yes. Some air companies let you carry the guitar onto the plane, but you should definitely inquire before hand.
Ibanez PGM301
Ibanez GRG170DX
Fender Telecaster MiJ - 1986
Swing T-Through

Ibanez TS9DX
Sovtek Small Stone - c.1985
EHX Big Muff
Kimbara Wah - c.1974
Boss GE-7

Orange Rocker 30 Combo

It should be fine, i flew from New york to London with my guitar in the hardcase and it was ok.
my guitar's a music man john petrucci signature. the case's music man as well. but the latches can't be locked. wonder if i should tape the case in loops.