Soup you going at it wrong. You shouldn't have any issues until you head to the airport. You PS3 ninjas is like bulls in a China store.
At the first spot, on the corner it sets up like this:
Building, billboard, building.
Climb to the roof of the first building, hop on the platform in the billboard to cross to the other building. Look down and you right on top of the enemy. Now you got cover and the high ground. Take them out, jump in the SUV to get the directions. You don't have to drive the SUV, all you need is for the yellow dot to pop up on your mini map. You can drive any car you want to the second spot once you do that. now that you got directions, post up and wait because back UPS are coming. Find cover and take them out. Easy. Drive to point 2.
At point 2 keep in cover, take the enemy out and advance on them when you can. There's PLENTY of cover there and even a health pack inside the trailer near the computer. Hack the computer and once finished, take out the back up. Once clear, head to the airport and handle up.
You dudes go in guns blazing or trying to run thru the mission too fast. If its no timer then don't rush. Clear the area, stock up on what they drop, and then do what you gotta do.
BE PATIENT!
Matt Schaub sucks....that is all