We have a well made map of all the locations where you do all the Under The Bridge and Knife Flight Aerial Challenges for Grand Theft Auto 5.
There are only 15 Knife Flight locations, and 50 Under The Bridge locations. What exactly is Knife Flight though? It entails flying your airplane on its side and crossing between two buildings. The Under The Bridge challenge is self explanatory.
Accomplishing all of these challenges will get you the Close Shave trophy, so if you’re interested in 100 %ing Grand Theft Auto, you will want to check this out. Get flying and the best of luck!
Source: Reddit