An airport tradition of years gone by is slowly making its way back to certain locations in the U.S., following massive changes in air travel security procedures after the terror attacks of Sept. 11.

Oakland San Francisco Bay Airport (OAK) in California announced this week it will be introducing guest passes for "non-passengers," for example.

Visitors can proceed to the post-security side of the passenger terminal to accompany friends or loved ones who are flying out, the airport notes on its website.

"Non-passengers" must apply online for security clearance up to seven days in advance of the day they want to visit the airport, according to the new process.

After people fill out the form, the Transportation Security Administration (TSA) will approve the visit by sending the "non-passengers" an OAK guest pass.

"Non-passengers" have to present the pass along with a TSA-approved photo ID, such as a passport or Real ID.

Before 2001, U.S. airports generally allowed almost anyone — even those without a boarding pass — to pass through security and wait at the gate.

After the Sept. 11 attacks, the TSA was created, and federal regulations began requiring airports to restrict access to secured areas.

These rules mandate that only passengers with a valid boarding pass may enter post-security areas.

A few other airports have begun to offer "non-passenger" passes, while others plan to roll them out in the future.

Cleveland Hopkins International Airport has a "hangout pass," while San Antonio International Airport (SAT) has a "SAT Pass," according to the airports' websites.

Kansas City International Airport, for its part, has a "guest pass."

Other passes include a "wingmate pass" at Philadelphia International Airport (PHL) and a "destination pass" at Detroit Metropolitan Airport.

In the "r/travel" forum on Reddit, one user asked, "How was airport security before 2001?"

Travelers jumped to the comments section to share nostalgic memories of flying before security tightened.

"One of the biggest differences is that unticketed people could come with you, so family could accompany you to the gate," wrote one person.

Another user responded, "One of my fondest memories is seeing my grandma as I exited the plane with my brother when my parents sent me out to see her."

Said a different person, "Going to the airport to watch planes was a big deal. Anytime one had to fly, or a friend or family member [was flying off], a whole group would accompany the traveler/s just to get there early and watch planes take off and land."

One person wrote, "You could go to the airport just to hang out, even if you had no travel plans."

The airport "reserves the right, at its sole discretion, to cancel the program."

Yet another user reminisced about "being able to see people off at the gate (or vice versa). Now you have to say your goodbyes, then walk half a mile to your gate alone."

The writer also recalled that "being able to greet someone at the gate was nice."

The Oakland airport noted on its site about the new initiative, "The OAK Guest Pass is not a permanent program. In response to exigent circumstances or operational needs, the Oakland San Francisco Bay Airport reserves the right, at its sole discretion, to cancel the program, cancel approved OAK Guest Passes or modify program rules at any time without prior notice." (Fox News)

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