Visiblement, c'était une plaisanterie.

"""
No doubt, the response by the FBI, and especially by United Airlines, is an overreaction, but Roberts also overstepped a line when he joked about hacking a specific plane as it was in mid flight. All three parties would do well to stand down, apologize, and move on now that it's clear to everyone there's no credible threat.
"""
ou pas. Allez savoir ;)

source: http://arstechnica.com/security/2015/04/researcher-who-joked-about-hacking-a-jet-plane-barred-from-united-flight/