PASSENGERS flying from more than a dozen airports in the US no longer need to show physical ID.

The Transportation Security Administration (TSA) has been rolling out a pilot program to speed up boarding across the country over the summer.

There are now 14 airports and four airlines participating in the scheme.

These include Alaska Airlines, American Airlines, Delta Air Lines and United Airlines.

Denver International Airport (DEN) is the latest airport to join the PreCheck Touchless ID program.

DEN has opened two security screening lanes in which eligible passengers can move through checkpoints using biometric facial recognition as their sole form of identification.

It comes after U.S. Homeland Security Secretary Kristi Noem said at a recent press conference that her "goal would be that someday someone could walk into an airport, walk through a scanner and go right to their airplane".

"This initiative is just one of many the Trump Administration is pursuing to usher in the President's vision for a new Golden Age of American travel," she said.

A new security line has also been announced for families.

This policy is known as Families on the Fly and these are reserved for parents with small children and military personnel.

The measure is now being trialled at major airports such as Orlando.

Noem has also teased that further security changes could be on the way.

TSA outlined the new biometric program in an explanatory video posted on its website.

As first reported by Aviation Week, TSA explained there is "no need to show physical ID or a boarding pass. Just your face gets you through."

In the video, passengers are told that instead of using a physical ID - such as a passport or driver's license - their faces are photographed by TSA using biometric cameras.

Anyone using the lanes must have an "active profile" with the airline on which they are traveling, said TSA.

There are also other requirements for anyone looking to take advantage of the new service.

Passengers must already be members of TSA's trusted traveler PreCheck program.

They are also required to upload valid passport information to an airline profile.

In a statement, American Airlines explained that TSA compares the facial image to photos passengers "previously provided to the government, such as those in a passport, Global Entry or a visa card".

TSA said the "images are not used for law enforcement, surveillance, nor shared with other entities," adding the photo and data "are deleted within 24 hours of your scheduled flight departure."

Phil Washington, CEO of DEN, said the facial recognition ID trial adheres to "the highest levels of safety and security".