Two ways this can go:
One, the world says 'this is the cost of a free society', and accepts the risk. Unlikely, IMHO.
The other is to trade security theatre for real security. The experience of travelling isn't too different from pre-11th September 2001 for most people. Security guards are probably a bit more professional, and checks are a little more thorough, but not especially onerous. Airports are actually designed to get passengers from the front door through to the gate as quickly as possible - more chance to spend money, and less time as a soft target the wrong side of the security check.
But if you happen to tick too many boxes on somebody's form, you get really in-depth screening. You'll probably miss your flight, even if you're a false positive. Too bad, but at least they didn't let a terrorist through.