So he went on record months before to approach the airline. Next, he tweets blatantly scary "what if" kinda things FROM A PLANE. Snoops snag the message, then snag him, snag his encrypted laptop, ask for keys, to which he says "warrant, or GTFO".
Maybe getting captured was part of his plan? Maybe he's gunning to get legal precedent set on the issue of crypto, passwords, the legal process, and self-incrimination. Bonus points for possibly exposing just how people are monitored online and if the feds can power through common disk crypto.
My guess is he did nothing wrong while on the airline, and even if he is legally compelled (via warrant or legal test case verdict), there will be no evidence of wrongdoing whatsoever.
Maybe the feds will finally show some of their cards?