[Covenantor]

How could the pilot be arrested? I mean he surely could be fired, but arrested?

Duh, the dude hijacked the plane and passengers.

He obviously planned this action as he had to review the route and submit his flight plan, check current weather conditions and prepare his charts, etc. It's not like driving a taxi.

Send his azz to Gitmo.

[Star Traveler]

United Airlines has responded to complaints with an apology to customers and an offer of compensation - and clarified that the pilot’s refusal was the result of a work dispute.

http://www.israelnationalnews.com/News/News.aspx/182185#.U6v2bNq9KSM

[ozdragon]

Equally concerning is who was on the ground crew.
The description of the plane’s physical condition may indicate that one or more members of the ground crew that vandalized the aircraft. It is a short step from vandalism to sabotage.

[Tzfat]

He obviously planned this action as he had to review the route and submit his flight plan, check current weather conditions and prepare his charts, etc. It's not like driving a taxi.

Airline pilots don't file flight plans. It is done hours before a flight by the airline's flight operations center. Often pilots know nothing about the proposed flight until they show up at the aircraft most often less than an hour before a flight. It may not be like driving a taxi, but to a professional pilot it might as well be.