For anyone who watched Bush’s speech on the aircraft carrier last night:
Behind both Bush and the crowd of sailors, there were two ‘seperate’ areas. It seemed that there were maybe 30 guys in either area. No uniforms (that I could make out), but they were wearing brightly colored jerseys (they looked kind of like bike jerseys to me.) Father’s speculation was that they were the flight deck crew, and wore the bright colors so to help be seen and thus not get run over by a jet plane. However - wouldn’t the Pres giving a speech be considered a formal occasion, and thus, they be expected to be in ‘regular’ uniform?
WAG: I would imagine that they were still on duty, and were just allowed a small break because of Bush’s visit. They probably didn’t have time to stop work, change cloths, listen to the speech, change back, and get back to work.
They are flight deck crew. The different colors represent their different jobs. Easier to make sure everyone is where they should be. The flight deck is a dangerous place. As to why they were still in “Teletubby*” dress…dunno. Maybe they were given a break to watch the speech since it’s probably taboo to launch and land with the CnC giving a speech on the deck. 
*No disrespect meant. That’s just what WhiteyWoman said last night.
Oh, no. Those guys weren’t on break - they were wearing the cleanest shirts I’ve ever seen on a carrier deck. I’d bet you a quarter they were all lined up to look pretty for the cameras (notice how not a single red shirt sat next to another red shirt?)
The ones in purple (grape shirts) take care of fuel; the guys in red do ammo; yellow shirts take care of the support gear on deck.