I heard that Zipair doesn't rebook on other airlines in the event of flight cancellation. My guess is that you'd be stuck waiting for the next available flight or that they would simply refund your ticket and you'd have to find your own alternative flight. It's truly a ULCC. I've thought about booking their full flat seat several times (for both work and personal trips), but their fares are all nonrefundable and nonchangeable, which is a deal breaker for me. If they had a flexible fare that allowed changes, I'd be more likely to book with them. (Of course JAL will never let them offer that, because it would cannibalize JAL's business.)