I'm starting fresh and seeing if I can complete bigger challenges earlier on to net large amounts of experience for a low-level character. Out of these challanges, the hang-time in vehicle challanges seem like they would be particularly easy to net.
Because of this, I'm curious: What's the earliest point in the game where one can net the 5 second hang-time achievement? If you don't know if your suggested location is the earliest location, that's fine; I have never gotten the 5 seconds of hangtime achievement and so would like to know where it can be gotten regardless of time spent reaching the location.