I was landing in PHL from ATL at the time the first plane hit. I didn't know anything about it till I was about and hour out of PHL headed for York PA in a rental car. My wife called me to see if I was OK and told me to turn on the radio. We (a coworker was with me) did go on to York and do the work we had gone there to do. We were there for three days I think, watching the news coverage during lunch and in the evenings and mornings but we, and everybody around us, continued to do our jobs and go about our lives while watching and wondering. We drove our rental car home from York PA to ATL (kudos to Hertz, who had quickly announced that anybody that had a car was free to drive it home, wherever that might be, with no special dropoff or mileage charges) a few days later.

The air travel shut down was disruptive to our business, which is all over the country and the world. One project manager took Amtrack to Hattiesburg, MS a couple of times and I drove to several job sites in the southeast that I might have flown to if it had been possible but jobs that were more than days drive away got put on hold till the travel situation normalized.

I don't recall ever really thinking that anything else was coming after the first day. The attacks were possible because we were oblivious. That ended by noon on 9-11. Any further attempts would have been exponentially more difficult to carry out at that point.

Airport security at the time wasn't really that different from what it is today. There were metal detectors and x-ray machines for your carry on bags. What was different was the attitude of the screeners. Remember, all of the hijackers walked right through security with the weapons they needed either in their pockets or in their carry on bags. They just weren't seen as weapons.

They obviously COULD be weapons but prior to that, hijackings had almost all been done with guns and a destination. That's what they were watching for - some individual nutcase that wanted to go to Cuba. Those hijackings were so rare and, really, so benign, that they were seen more as an inconvenience than a threat. The planes landed, got refueled and came back to the US.

Terrorist hijackings were something that happened in the middle east with the hijackers trying to extort prisoner releases and the like. Nobody, at least nobody outside some small group in the intelligence community, ever thought that a US domestic flight would become a target for that. And we never did and never have. But we did learn that we can be targeted for random, cowardly attacks on innocent civilians mean to disrupt our lives and frighten us.