Americans, who are expected to pass through airports in near record numbers this year, can expect to be sniffed by more dogs, scrutinised by more armed officers and faced with longer security lines.
The reason: Brussels.
A plane carrying Transportation Security Administration head Peter Neffenger was nosing up to the arrival gate in Brussels on March 22 when the first of two bombs that killed 16 people exploded in the terminal.
A third went off a short time later in a subway, killing 16 more people.
"Here's what we do to make sure that that doesn't happen here," said Neffenger, who was on his way to a security meeting when the bombs went off.
"There's a lot more patrolling of public areas here than I believe was the case in Brussels.
"We have explosive sniffing dogs moving through the fronts of the big airports. And there's a lot of attention paid to people moving big items through airports."
Neffenger's remarks came two days after a Capitol Hill hearing where he was grilled about airport security by Senator Bill Nelson who told him: "The only person who is going to get the airports off their duff to limit the access into their airports is going to be you and your administration."
The Senate, eager to act after the Brussels bombings, voted to increase vetting of airport workers, expand the number of TSA viper teams that sweep through airports unannounced to stop and search suspicious people, and double the number of TSA's bomb-sniffing dogs.
"There's some things you have to do after Brussels, and one of them is to realise that public areas of the world are vulnerable, by definition," Neffenger said. "It helps that we have a vast national intelligence network.
"I'm comfortable that in the United States in particular, we are doing about as much as we can do to track, to identify and to pay attention to people of concern. If you've made a reservation, your name is automatically bounced against databases."
He worries that may not be enough to stop a repeat of Brussels on US soil.
"Would that have been enough to have caught that? I can't say that for certain, but I will tell you that there's a lot of attention being paid to just that kind of potential happening."
Neffenger said people will see a much more visible police presence at airports in the months to come and an increase in bomb-sniffing dogs as rapidly as they can be trained.
He said passengers should expect more random searches both as they enter airports and after they pass through checkpoints into secure boarding areas.
Neffenger said local law enforcement officers may also conduct random checks of cars and taxis driving toward the airport, a practice already in place in Los Angeles.
"You have to get away from thinking about a perimeter. I'm much more interested in thinking about the security environment that is essentially from the moment that you make a reservation to the moment you physically arrive at the airport."
There have been suggestions that extending the airport perimeter in Brussels might have deterred the bombers, who apparently did not have tickets to board a plane.
'Man in hat confesses'
After nearly three weeks of frantic searching, Belgian authorities announced they had finally identified the elusive "man in the hat" spotted alongside the two suicide bombers who blew themselves up at Brussels Airport: It was Paris attacks suspect Mohamed Abrini.
Belgium's Federal Prosecution Office said the recently detained Abrini - the last identified suspect at large from the deadly November 13 Paris attacks - had also confessed to being the vest- and hat-wearing man linked to the Brussels bombers whose image had been widely circulated by authorities.
"After being confronted with the results of the different expert examinations, he confessed his presence at the crime scene," they said in a terse statement.
The revelation that a Paris attacks suspect escorted two of the Brussels bombers to their deaths at the city's airport is the strongest sign yet that Isis (Islamic State) attackers who brought mayhem to both European cities - killing a total of 162 people - were intimately linked.
Abrini, 31, was one of four suspects charged with "participating in terrorist acts" linked to the March 22 Brussels bombings that killed 32 people and wounded 270 others at the airport and in the city's subway.
The prosecutors said Abrini, a Belgian-Moroccan petty criminal who was detained on Saturday in a Brussels police raid, threw away his vest in a garbage bin and sold his hat after the March 22 bombings.
Prosecutors did not respond to calls seeking further details.
Surveillance footage put Abrini in the convoy with the attackers who headed to Paris before the attack that killed 130 and injured hundreds.
Abrini was a childhood friend of Brussels brothers Salah and Brahim Abdeslam, both Paris suspects, and he had ties to Abdelhamid Abbaoud, the Paris attackers' ringleader who died in a police raid soon after.
Brahim Abdeslam blew himself up in the Paris bombings while Salah Abdeslam was arrested in Brussels four days before the attacks there.
Abrini was also believed to have travelled to Syria, where his younger brother died last year in Isis' Francophone brigade.
- Washington Post-Bloomberg, AP