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.

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"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.

Mohamed Abrini. Photo / AP
Mohamed Abrini. Photo / AP