One point here is to remember that, literally, thousands of airport employees do not pass through any form of security check on their way to work each day. They arrive at the airport car park and get on to a shuttle bus which oftentimes drives straight into the secure airport area. The only check required is possession of an airport employee ID card.
Excuse my "profiling" but it is quite apparent that many of these people are recent immigrants (very little english) and are from states which are not friendly to the USA. We know most of these people are perfectly reliable but this situation is an open door for terrorists to gain access to any aircraft they wish.
It does not challenge the intelligence to see that a planted employee could bring a bomb or firearm onto the airport and leave it a position where it can be retrieved later by a passenger terrorist accomplice.
There is as yet no proof of how the terrorists got their "weapons" onto the aircraft so speculation about airport or airline security failures is premature. In the US each aiport designs a security system which is then approved by the FAA as meeting its standards. In some cases individual airlines are responsible for TERMINAL access security which covers passengers, airport terminal employees and crew members. I have no idea about what type of pre-employment screening is needed for airport ground workers who do not go through this terminal security before they are issued with an ID card which allows them virtually unrestricted airport area access. Clearly this complicates the allocation of responsibility because hundreds of separate companies could be granting airport access to their various employees.
Ironically, the FAA's "window dressing" security checks prevent a crewmember from possessing any sort of weapon at work, the very situation which in this case could have saved 5,000 lives.
[ 15 September 2001: Message edited by: BOING ]
[ 15 September 2001: Message edited by: BOING ]