“In the near term, pilots will be looked at with a bit more suspicion,” said former US Airways pilot John M. Cox, now CEO of the consulting firm Safety Operating Systems. “This rogue pilot is not the first one and sadly will not be the last one.”

Since the Sept. 11 terrorist attacks, aviation security has focused on protecting pilots from passengers — not the other way around. Fliers are screened for guns and explosives, but some pilots are allowed to carry their own weapons. Also, pilots might undergo mental health screenings when hired, but once they are on the job there is very little renewed testing.

“Right now, I don’t think there’s anyone who isn’t worried,” said Steve Serdachny, an airline passenger on his way from Toronto to Moscow, via Helsinki. “Flying is a safe form of transport, but you can’t stop crazy. If someone decides to act in a crazy manner, there’s nothing anyone can do about it.”