Experts say there should be checks before someone is able to enter an airport.
The terror attack in Brussels has exposed a major weak spot in airport security - cars and people are not screened until they reach security machines deep inside terminals.
Read: Brussels Suicide Bombers ID'd as Surviving Suspect Continues to Elude Police
Counter-terrorism expert Tony Roman of Roman and Associates is calling for a change.
"Cars at the terminal, a bomb could be in them and we can lose a lot of people," he told IE.
It's an extraordinary challenge, stopping terrorists before they reach airport terminals. At most airports, you are dropped off at the terminal, with your bags and you walk inside.
He added: "We have to move security away from the terminal. It is a minor inconvenience for a lot of protection."
Security analysts are scrutinizing surveillance video showing the Brussels terrorists.
In surveillance footage, the suspects appeared relaxed as they walked through the airport.
Read: Mom of Twins Who Was Flying to New York is First Confirmed Victim of Brussels Attacks
Carnegie Mellon social psychologist Nichole Argo studies terrorists and told IE: "The reason that the bombers can carry out a killing mission like this so calmly is because they view the victims as the enemy."
University Of Rhode Island professor Jimmie Oxley, an explosives expert, spoke to IE about the bombs used in the airport attack.
"I think there were also bombs in the carts they were pushing," she said.
Watch: Belgian Neighborhood of Molenbeek Known For Breeding Terrorism, Experts Say
