Nearly 20 years after airline passengers were first required to remove their shoes for security, the policy is being phased out.

The Transportation Security Administration (TSA) is planning to allow passengers to keep their shoes on when they go through the general security line at many major airports across the country, two sources told ABC News.

An unexpected memo went out to TSA officers across the country last week stating the new policy will allow all passengers to keep their shoes on in all screening lanes at many airports across the country, starting Sunday.

The goal is to roll the new policy out to all U.S. airports shortly, according to the memo. Previously, only passengers in the TSA PreCheck line were able to keep their shoes on in most cases.

The transportation agency has spent years looking for an innovative way to allow passengers to move faster through the security checkpoints.

Passengers who trigger the alarm at the scanners or magnetometers, however, will be required to take their shoes off for additional screening, according to the memo.

This is a major shift since TSA began requiring passengers to take their shoes off in 2006.

The policy came five years after Richard Reid tried to blow up an American Airlines flight from Paris to Miami with explosives packed in his shoes. The explosives failed to detonate and Reid was held down by fellow passengers and the flight crew.

ABC News has reached out to TSA for a comment.