Its not like 9-11 at all. They put FAM's on flights (useless as they are), they implemented the TSA (ha) ... and people felt re-assured. The chance of a 9-11 style attack after that basically collapsed because everyone was on notice.
sure, people were flight-shy..

Now there's a virus of non-trivial lethality making the rounds(apparently) stealthily. People are saying "no thank you". Hopefully in a few months there will be viable treatments available and progress with some vaccine candidates.