[Ramius]

Im sorry, but I think this was an over-reaction. A small cessna is no more of a threat than a U-Haul. Where it is a greater threat (NBC attack), evacuating buildings and running around outside is pointless, and perhaps a more dangerous place to be.

I don't think there is always the luxury of knowing immediately what sort of aircraft it might be. That's something that you find out some precious minutes later, and people need to start evac immediately.

[El Gato]

I don't think there is always the luxury of knowing immediately what sort of aircraft it might be. That's something that you find out some precious minutes later, and people need to start evac immediately.

Exactly, all you have is a blip on the radar, with or without a beacon response. (If the transponder was on at all, it probably was squawking code 1200 (Visual Flight Rules, not under air traffic control)). It could easily have been an old airliner, such as a DC-6 or Convair 240/340/440/580, or even an old DC-3. Any of those could carry a significant payload.