hijacking incident; takeover case
Refers to an event or case involving hijacking, such as of an airplane, ship, or vehicle. Often used in news contexts.
The perpetrator of that hijacking incident has not been caught yet.
The news reported on an airplane hijacking case.
乗っ取り is the act of hijacking or takeover itself, while 乗っ取り事件 specifically refers to the incident or case.
ハイジャック is a more direct loanword for 'hijack', often used for the act itself. 乗っ取り事件 is a formal compound for the incident.
Compound of 乗っ取り (のっとり, 'hijacking, takeover', nominal form of 乗っ取る) and 事件 (じけん, 'incident, case').