Knife Flights

Knife Flights are a miscellaneous challenge in Grand Theft Auto V that requires you to use an airplane (fighter) and knife in between 15 buildings around the game world to complete part the "Close Shave" achievement/trophy. You'll need to complete all 50 Under the Bridge challenges in order to fully complete the "Close Shave" achievement/trophy.

8 of the 15 bridges also count toward 100% Completion.

Tips

 * It is highly recommended you complete Flight School at least up to the "Knife Flight" mission as knifing can prove to be quite difficult.
 * You can steal a fighter jet from Fort Zancudo, though this may pose it's own problems.
 * It is advised to use the Quick Save option in the phone menu when preparing to knife through two objects as if the stunt goes completely wrong, you can quickly restart from that save point with the aircraft fully intact.