Some Gnomes are obvious and cowardly hiding behind the legs of the cutouts of the employees. If you can get thru and crash into the Gnome it vibrates violently and burrows headfirst into the ground. Strangely satisfying! My goal is to get to the gnome without hitting the workers. It's like getting thru the entire obstacle course: only certain aircraft can do it.
In at least several airports the gnome has an invisible protective barrier that either makes your drone stop and land or crashes it like a glass barrier - I 'haven't found any way past that yet (having too much fun doing actual flying to waste the time)
The simulations don't let you go everywhere you should theoretically be capable of going - go too far in the wrong hallway and it just stops, period despite there being plenty of room, yet it will go all the way thru under any of the bridges at the Japanese airport. But at the same airport you can't fly down all of the passages around the buildings. The SPACE is there, The drone just will not fly in it. Just how far they had time to develop the databases, I guess.