Wanted to share this little glitch. Not sure if it would be useful whatsoever considering that main menu warping to missions exists. Perhaps for 100% it could be useful for moving around the overworld faster to collect things or go to side missions.

This video contains several instances of the glitch, one being at 2:09:52 in the video, for example.

Hopefully that all made sense in the context of the video.

Sadly, there seems to be invisible walls surrounding the townscape, even an invisible ceiling. Haven't managed to get Lem out of bounds with this yet.

Depending on the angle that you launch at, perhaps you could out-speed the loading of areas as you pass through them to end up out of bounds that way.

Tested this with cars, and it also works. I believe that it might not be possible to cause a launch without getting into the vehicle. The same goes for bikes.