Not every airport responded the same way, but at SFO they brought in extra police and bomb sniffing dogs. It shattered a certain Christmas Day ease that some passengers say they had slipped into.
"Right when I got upstairs I just saw like five police just walking all together," airline passenger David Lagle said.
In response to the attempted airline terrorist attack, San Francisco police deployed their tactical unit to SFO. They called it a high visibility operation, but the SFPD would not say how many officers were on duty.
"It is concerning, it is very concerning; hopefully they'll investigate and find out how he did it," Lagle said.
SFO says it stepped up its luggage screening process after news of the failed attack.
It is believed the alleged terrorist breached security in Nigeria, but ABC7 aviation consultant Ron Wilson says explosive detection is still an Achilles heel at American airports.
"Explosives going through security at the security checkpoint is really a hole in the system, it's one thing that they are pursuing, it's a requirement of Congress on the 9/11 commission that they do pursue it but they really haven't got a lot of definitive information and technology on it," Wilson said.
Wilson says the best deterrents are bomb sniffing dogs and explosive detectors, but both are used only randomly or when there is reason for suspicion.
"Lately, I thought everything would be safe, I probably went on a couple of vacations this past year and I felt pretty comfortable going out," traveler Robert Deleon said.
Some passengers say they had slipped into a comfort zone prior to today's attack.
"Something like this will probably make the pendulum swing back the other way," airline passenger Scott Wilber said.
Oakland International Airport stepped up its curbside security and San Jose Mineta International Airport says it also took extra measures, but they were not publicly visible.