The 300,000 feet is accumulative so if you play long enough getting decently high launches
you'll eventually get it. I had trouble because I didnt think it had anything to do with
being accumulative and thought that the UFO easter egg that can be seen in south facing
windows. Sadly the UFO doesn't actually exist in game. (Unless there is an end game unlock
or something but I doubt it).

you can get into the pipe on the factory to launch you in the air.and the UFO thing is SO
real i saw it.