The TSA said it has spent $80 billion on aviation security since its inception shortly after the 9/11 attacks. That does not include perimeter security.
"We were investing all our resources in the front door, which were the passengers and their bags," said Ron, the security consultant. "And we left the back door open. And that was the perimeter and access to aircraft."
Christopher Bidwell, a security specialist with a trade group representing airports, said the facilities continually evaluate ways they can best secure airfields and work with the TSA to comply with federal requirements.
"In the U.S., we have a very effective aviation security system in place," said Bidwell of the Airports Council International-North America.
AP National Writer Martha Mendoza in San Jose, Calif., contributed to this report.