Definitions

1. noun

a person who takes control of an aircraft by force or threat, typically with a view to extorting money or other concessions from the passengers or crew.

“The FBI was investigating the hijacking and the involvement of a suspected highjacker.”

2. noun

a person who seizes control of a vehicle, especially a plane, for unlawful purposes.

“The plane was taken over by a group of highjackers who demanded a ransom in exchange for the safe release of the passengers.”