Windshear on takeoff? The wind was NASTY in Pittsburgh overnight and would match Philly's experience today. We dropped over 60 degrees in temperature in less than 12 hours and will be back up another 50 degrees tomorrow.
I've read that the aircraft was airborne momentarily. We're not talking inexperienced pilots at USAirways. So if they were airborne one would assume they reached the proper V2 at least, right?
Human Factors - we all know they shouldn't take their bags... I would "ass"ume that if it was dire consequences most wouldn't care about the bags. Maybe it wasn't overly violent that many PAX grabbed bags thinking it wasn't as serious?
Just pondering...