Washington (CNN) The Transportation Security Administration is considering eliminating passenger screening at more than 150 small and medium-sized airports across the US, according to senior agency officials and internal documents obtained by CNN.

The proposal, if implemented, would mark a major change for air travel in the US, following nearly two decades of TSA presence since the terrorist attacks of September 11, 2001, and comes as the Trump administration has stepped up screening measures for items such as laptops and tablets.

Internal documents from a TSA working group say the proposal to cut screening at small and some medium-sized airports serving aircraft with 60 seats or fewer could bring a "small (non-zero) undesirable increase in risk related to additional adversary opportunity."

The internal documents from June and July suggest the move could save $115 million annually, money that could be used to bolster security at larger airports.

According to the proposal, passengers and luggage arriving from these smaller airports would be screened when they arrive at major airports for connecting flights instead of the current practice of joining the already screened population at the larger airport. The high-volume airports have greater capacities and more advanced security measures than smaller locations, the documents say.

CNN terrorism analyst Paul Cruickshank said it was "stunning that this is even seriously being considered."

"Al Qaeda and ISIS still regard aviation as a priority target -- that includes aircraft where you have fewer than 60 people on board," he said. "They would see that as a way to hit the headlines. They would see that as a way to inflict severe economic damage on the United States. If you have an aircraft of 50 or so people being blown out of the sky there is going to be a great amount of panic and there will indeed be significant economic reverberations, and of course significant loss of life."

"This is so dangerous," a TSA field leader at a large airport said. The individual is not authorized to discuss the matter publicly.

Two senior TSA officials, who asked not to be identified, expressed serious national security concerns over the proposal. They said the idea was explored as far back as 2011 and has been resurrected. The documents referred to some 150 small airports in addition to some midsize ones. TSA currently screens passengers at 440 airports, according to its website.

The working group determined that the policy change would affect about 10,000 passengers who are screened by 1,299 TSA employees daily, which amounts to about 0.5% of the people who fly out of US airports on any given day. The report not list specific airports that could be affected by the policy change.

TSA spokesman Michael Bilello said the study reflects a recurring debate within the agency about its legal requirements.

"This is not a new issue," he said via email. "The regulations which established TSA does not require screening below a certain level, so every year is 'the year' that TSA will reconsider screening." Bilello did not respond to a request for the text of the regulations.

The two TSA senior officials said the level of activity around the proposal this year -- the formation of a working group to conduct a risk and cost analysis -- mean this is more than an annual exercise.

The documents said a TSA working group of 20 people, including a representative of the agency's administrator's office, met on June 21 to examine the potential risks of the policy change. An internal TSA memo dated July 17 from TSA Director of Enterprise Performance and Risk Strategy Jerry Booker to the TSA administrator's chief of staff, Ha Nguyen McNeill, outlines the group's findings. It contains no formal recommendation.

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Small airport security issues

The concept of rolling back security at regional airports recalls the coordinated attacks that brought the TSA into existence.

Two of the September 11 attackers first flew from an airport in Portland, Maine, to Boston before boarding American Airlines flight 11, forcing entry to the cockpit and steering it into the North Tower of the World Trade Center. While Portland's airport likely would not be included in the proposal because of its volume of passengers, the 9/11 attackers perceived the airport to be less secure because of its relatively small size.

The proposal asserts that small aircraft would not be "attractive" to terrorists. The documents conclude that attacks with small aircraft would not as attractive a "payoff" because "the potential for loss of life" would be lower than terrorists could achieve with larger planes.

Juliette Kayyem, who was an assistant secretary for intergovernmental affairs at the Department of Homeland Security in the Obama administration, said small planes could still be weaponized to cause major loss of life.

"People, weapons, dangerous goods and what's boarding the plane are all potential risks," said Kayyem, a CNN analyst. "TSA is falling into the trap that this is just about terror. A gun could be brought on board too."

Shift from earlier administration rhetoric, policy

The proposal under consideration by TSA is different from the agency's current approach to screening passengers.

Since TSA's inception in 2001, the trend has mostly been toward more enhanced security measures, including limiting gels and liquids in carry-on bags, requiring more advanced screening and directing passengers to remove shoes and belts for screening.

In June 2017, then-DHS Secretary John Kelly announced a laptop ban from carry-ons affecting nearly 280 airports in more than 100 countries.

"Terrorists want to bring down aircraft to instill fear, disrupt our economies and undermine our way of life," Kelly said . "And it works, which is why they still see aviation as the crown jewel target."

He continued, "The threat has not diminished. In fact, I am concerned that we are seeing renewed interest on the part of terrorist groups to go after the aviation sector -- from bombing aircraft to attacking airports on the ground."