Something like that...I've seen them (usually men--not sure if there are any women--dressed all in black like ninjas--no their faces are not covered!) getting off one plane and and hopping right back on another one after quickly flashing some sort of ID at the GAs. It would seem to make sense that they would have assigned routes and not just picking them at random, but who knows...maybe they are just told to be airborne for how ever long their shifts are...