The list of airports where you can skip the TSA PreCheck line and use a facial recognition scan instead of your ID is growing

• The TSA is rolling out its facial recognition tech at more airports.
• United Airlines is testing a "Touchless ID" plan at O'Hare which doesn't require a physical ID.

You won't need a boarding pass or an ID to get through security if you're using TSA PreCheck at some airports.

The Transportation Security Agency program means quicker screening for trusted passengers. Applying requires a background check and costs $78.

Now it is offering even faster screening as it rolls out facial recognition technology at some of the US' biggest airports.

As The Points Guy first reported, United Airlines has recently updated its website to show that "Touchless ID" is available for its customers at Chicago O'Hare and Los Angeles International Airport.

However, passengers will still have their physical ID checked afterward at O'Hare because it's testing the feature for security checkpoints and bag dropoff, per TPG.

A spokesperson told the outlet it expects the test run to be fully implemented by May.

And at LAX, passengers will be able to check bags with the new system from March, they added.

United's website says that after checking in for a flight on its app, passengers can opt-in to use a face scan as their ID.

"We plan to add TSA PreCheck Touchless ID to more bag drop counters, security checkpoints, and boarding gates in the future," it adds.

Delta Air Lines also makes use of the technology. Its passengers at Atlanta, Detroit, LAX, LaGuardia, and JFK can check bags and go through security without needing to show a physical ID.

American Airlines' "Mobile ID" offers the same benefits, but only at Washington Reagan Airport.