You should keep your hopes up for jets.
If you go through the achievements, you'll see there's one for breaking the sound barrier, another for exceeding Mach 2 and another for exceeding Mach 3.
I'm not really interested in paying another $20 or whatever to fly supersonic over Hawaii. Rather do Mach 3 and go supersonic all the way to Canada in my good old fsx
Have you seen the recommended hard disk space? It's 30GB. If Flight doesn't offer scenery for the whole world, it will at least offer quite a lot.
There is also an award in Flight called "Globe Trotter" or something like that. I don't think they would've called it that if you can't trot the whole globe.