The IFSCL (code lyoko supercomputer interface) is a fan destkop simulation game. It reproduces exactly the Supercomputer of the animated show : CODE LYOKO, and put you as an operator guiding his friend to fight monsters.
Currently working on one of the things I really wanted to implement with 3D : flying ability. Though it's very complicated but I've found a way to have something decent for flying lyokoguides (which are overvehicles, frolion, mantas...), there should be some 'aerian paths' I will define manually on each sector that a flying lyokoguide will be able to use.
So basically, most of the time, they will still be using ground paths, but I will place Flying Paths on the most logical spots so they will have 'shortcuts' on their own ;)