That almost killed it for me, but you should have persisted! The Las Vegas style city was awesome and had some of the best missions. Well worth going back and completing those flying missions for>
That was a bitch of a mission. Thing is, just go through it slow, don't worry so much about the time limit. If you screw up just remember the layout and where to go ultimately.
I know I hated that mission and stopped playing for a while. If I did play it was just mindless roaming and general fun. I then tried it out and beat it after a fifth attempt. :hatsoff: