After you finish the task "Hating the Haters", you should have a scooter (named Faggio). Simply go to any long straight road or bridge, do a wheelie by pulling LS all the way down (towards you). After several seconds, this achievement should be unlocked.
Note 1: It's easy on scooter because it won't allow you to go over.
Note 2: You can do this on any long straight bridge by wheeling on the side of bridge. It's usually safe. No need to drive far to the airport
Note 3: If you want to unlock this achievement with "Walk Free" (losing 4 star wanted), simply go to the airport and do it on the runway.