ROBERT SIEGEL, HOST:
The airport in Brussels will remain closed until at least Saturday after the attacks there. Here in the U.S., security at airports is on high alert. Security experts, politicians and travelers say they're concerned about the weak spot the bombings exposed - the area between terminal entrances and screening checkpoint. From Chicago, here's NPR's David Schaper.
DAVID SCHAPER, BYLINE: Just as there is at airports all across the country, there is an increased security and police presence here at Chicago's O'Hare Airport, but that doesn't mean that travelers are without concern. In fact, to some, the security measures don't go far enough.
DAN CICERO: The more the better, in my case - you know, whatever it takes to keep us safe.
SCHAPER: Forty-two-year-old Dan Cicero is traveling from Kentland, Ind., Eau Claire, Wis., on business.
CICERO: I'm not talking, you know, guys with machine guns or anything like that, but, you know, more and maybe more of a police presence.
SCHAPER: Fifty-year-old Lisa Paley, who is returning home to New Jersey from a business trip to Chicago, agrees airport security can be improved.
LISA PALEY: I do think that we have good security, but the security is behind the point where that issue occurred yesterday at the airport, so I think you have to have some concern about what's happening.
SCHAPER: The Brussels airport attackers exploded bombs in an area inside the terminal but before the security checkpoint lines. And Paley says that vulnerability is troubling.
PALEY: I think we have to acknowledge we're in a situation which is always changing, and I think that they're going to have to continue to look at what security means at the airport.
DANIEL WAGNER: I would suggest that we're more at risk than we think.
SCHAPER: Daniel Wagner is CEO of the security consulting firm Country Risk Solutions.
WAGNER: If you think about the way things were done in Brussels and have been done in other places, literally people have to only walk in, and they can attack at will.
SCHAPER: In U.S. airports, the TSA is often not responsible for security at the curb and inside around those check-in kiosks and baggage check-in and claim areas, and that's a concern of Massachusetts Congressman Bill Keating, ranking Democrat on the Foreign Affairs Subcommittee on Terrorism.
BILL KEATING: The implementation of that security runs right across the board. Sometimes it's private security. Sometimes it's local police hired out, paid for by the municipal or airport authority or whoever runs it. And that jurisdiction is not clear the way it should be.
SCHAPER: Security consultant Wagner suggests U.S. airports establish pre-terminal screening before travelers enter the facility.
WAGNER: That is a common approach in many countries around the world. You cannot even get in the terminal until your bags and your person have been prescreened. That is through an x-ray machine both for the bags and for the individual.
SCHAPER: Enhancing security to that degree would be costly, and Wagner says he's not sure he sees a great enough sense of urgency yet for Americans to be willing to pay for it. In addition, such pre-terminal screening could create long lines outside of terminals and bottlenecks of traffic congestion. Again, Congressman Bill Keating.
KEATING: What's more likely, given resources and the difficulty of doing that, is that there could be a random screening.
SCHAPER: Keating says he requested a government accountability study on how to improve airport perimeter security a year ago, which he says will be released soon. But most experts agree it's nearly possible to make public airports completely secure from terrorist attacks, especially when those terrorists are willing to take their own lives when taking the lives of others. David Schaper, NPR News, Chicago.