Some airport security, such as agents at the security checkpoints, you cannot miss. Other aspects you may never see.

Despite that, a Government Accountability Office study released Tuesday, said parts of the system are lacking, specifically the outside perimeter.

The GAO says Homeland Security and the Transportation Security Administration have, "Generally not achieved," when it comes to seven areas of security.

"We are not where we need to be as the traveling public continues to travel,” said Congresswoman Sheila-Jackson Lee during a hearing this week in Washington. “So I am obviously trying to create a sense of urgency.”  

That's why Transportation Safety Administration officials were called to Congress today to explain.

Locally security experts note there are only broad rules on how to secure airports and those come from the FAA.

"The TSA should probably go through a program of assessment vulnerability,”

Mark Mancuso, the Houston Airport System’s security chief. “Look at airports and determine you know what are their assets? What are their critical assets?"

Because, no two airports are the same. Look no further than Houston's major airports.

Hobby on the city’s south side is small and surrounded by development, but Bush Intercontinental is seven times bigger.

Vast amount of area. Wooded terrain. Places where you can hide.

Houston's airport system security chief Mark Mancuso says the security here is better than many airports.

He points to the layers you can and can't see, but it is not just the perimeter.

In addition, the GAO report highlights air cargo screening and security as a problem...

The TSA knows it.

"From a security point of view, we have definitely closed down the vulnerabilities that may have existed a year or more ago,” said TSA administrator Kip Hawley. “That is not going to take away from the fact that we still have more to do."

Interestingly just as the feds continue their talk about lacking air cargo security.

Cargo traffic in the Houston Airport System is on the rise. Just this week, two new weekly cargo flights from Asia were announced.