I have had guns pulled on me, been subjected up to 5 separate searches just to board a domestic flight! I have missed flights when I was there for more than 3 hours! All because a terrorist from South Yeman used my very common name as an alias 1 time!
In the early days after 9/11 they were grossly over-reacting. While waiting in a velvet rope square next to a cop while American Airlines were trying to unfreeze their computer system since my attempt to check in caused their whole system to freeze, not allowing anyone else to check in, I called the FAA. The young man who first spoke called out and said we have another ____ (my name). His supervisor got on the phone laughing. She told me it was the FBI's fault and I would have to talk to them to clear my name. She asked if I was in an airport to which I replied yes. She told me to go to a news stand and look in that months issue of the New Yorker magazine. When I was eventually freed I did, and I saw an article about people with my name and names similar to mine being stopped and harassed like I was.
The FBI blamed it on the FAA with both saying the other was the only one who could take my name off. Eventually, I became a frequent flyer of one airline and could check in electronically and not have a problem. They assigned me an FBI agent that I could have people call to clear me faster except he never answered his phone.
I don't fly much anymore but when I go to Brazil this year I have to plan on getting their 6 hours early. They never take ANY NAMES OFF THE DAMN LIST! The terrorist have won! They use common names as an alias to screw up thousands more people that fly!