“I would almost call it a viral cult phenomenon with these cards,” Captain Brian Ferguson told Fortune. “Out of nowhere, overnight, almost everybody’s asking for cards, everybody wanted these.”

In a viral TikTok video posted in November with over 30 million views, a passenger documented the process of securing his first-ever Delta trading card, and viewers were shocked to learn of the shiny collector item’s existence. 

“Just googled ‘Delta Airlines trading cards.’ Mind blown,” one user wrote in the comments. Another matched their surprise: “We’ve been worrying about airline points when the real game has been airline trading cards this whole time.”

The video sparked a social media craze, with a flood of fellow frequent fliers clamoring to ask flight attendants for the chance to knock on the cockpit’s door and secure their post-flight prize.

The popularity extends beyond TikTok. Reddit users of the r/delta community, which boasts over 138,000 Delta fans, have shared images and videos of their favorite illustrations, including a framed showcase brandishing 36 cards.  

“I was nervous to pop [my] head in the cockpit but the pilot immediately invited me in and offered to take a photo!” a user gushed in a post with 2,000 upvotes. 

The sudden intrigue shocked Delta pilots like Ferguson, who recently told Fortune that while he’s always had a stack of cards on hand in hopes a passenger might pop the top-secret question, the volume of requests he’s received in recent weeks has skyrocketed. He now routinely gives out up to 10 cards per flight.  

Demand was so high that by the Christmas holiday rush, Delta was “ordering and having these printed as fast as they can,” he said.

A seasoned pilot and retired Navy reservist with over 30 years of experience and a brief stint on the set of Top Gun: Maverick, the 54-year-old is never without a card on hand, and keeps a personal stash at his home in case of emergencies. 

Between flights out of Los Angeles International Airport, the longtime pilot revealed to Fortune how passengers can score a card and hinted at a top-secret addition coming soon.

In-flight connections 

While Gen Z and millennial TikTokers may just now be catching up to the trading card trend, the phenomenon is not new. Launched by a group of flight operations employees in 2003, Delta’s cards are exclusive to pilots and feature images of the aircraft they pilot, according to a spokesperson. Delta says it introduces new designs into circulation every five years, and the artwork is voted on by the Fortune 500 airline’s nearly 17,000 pilots. 

The first-ever installment featured a limited-edition McDonnell Douglas MD-11 manufactured by Boeing that was scheduled to retire the next year. Now in its sixth edition, the full collection boasts over 60 variations with holographic designs and aircraft “fun facts” generated by pilots. 

Ferguson is well known for constantly restocking his stash: “The joke in the office here is I give out so many that they’re going to just start delivering them to my house.”

His frequent trips to the pilots’ lounge to restock before every flight were so noticeable that last summer, a colleague gifted him with 250 cards to give away, although he hasn’t “quite burned through all of those yet.”

“Somebody made a joke, ‘You sell these on eBay? What do you do with all these cards?” Ferguson recalled, to which he responded: “Well, I’m giving them to passengers.”

He’s not alone. In 2023, Delta handed out over 1.5 million cards, according to a spokesperson. The “customer engagement tool” is one of the many reasons the airline is a frequent high flier on many annual rankings, including the 2024 Fortune World’s Most Admired Companies list. The Atlanta-based airline also earned bragging rights as the “Top U.S. Airline of 2023,” according to the Wall Street Journal’s ranking. 

Delta’s customer service is paying off, literally. The airline reported fourth-quarter earnings results in January, capping off 2023 by doubling its quarterly profit and netting a record full-year revenue of $58 billion. The company is also sharing the wealth: Delta CEO Ed Bastian announced Wednesday that the airline was paying out $1.4 billion in profit-sharing payments to its more than 100,000 employees. The bonus check equates to 10.4% of their annual salary.

Aviation enthusiasts

While gladly given out for free as long as you ask politely, Delta’s trading cards are still frequently sold online by aviation enthusiasts, with one eBay listing promising a complete set for $3,000. 

“I get requests for cards from people that are middle-aged and ages that you wouldn’t think are the typical demographic for one of these cards,” Ferguson said. “A lot of them are collectors; a lot of them are going through a second career in aviation.”

Most requests tend to be from a younger crowd and their parents, but the captain encourages passengers of all ages to visit him and his copilot in the cockpit after landing, even the skeptical crowd who fear they may be pranked.

“About 30% of them are people in their twenties and thirties that will come up and ask for a card,” he said. “About half of those will come up and kind of look over their shoulder like it’s a secret and go, ‘Hey, is this trading card thing real?’”  

However, Ferguson, the ever-experienced trading card dealer, is always prepared for a smooth encounter. 

“I usually have one in my hand in my pocket for just such an occasion. I’ll flip it up really quick and go, ‘I was waiting for you to come up,’” he said. 

His aim is to help families and fans make lasting memories, and not just by giving out a coveted trading card or a pin shaped like a pair of wings. He routinely offers pictures with passengers, a chance to sit in the captain’s seat, and the opportunity to flip a switch that illuminates every light on the flight deck. 

“You never know, but maybe one or multiple of these people will grow up to be a Delta captain someday,” he said.

More airline trading cards

Delta isn’t the only airline offering aviation memorabilia. 

Frontier Airlines has trading cards featuring the endangered animals and threatened species displayed on its aircraft, including mascots Griz the Bear, Otto the Owl, and Flo the Flamingo. According to a spokesperson, all customers, including adults, can ask flight attendants for a free card during their flight. 

United Airlines previously offered limited-edition trading cards in June 2023 to celebrate the airline reaching 1 million followers on Instagram, but only 100 packs were given out. However, the airline still offers plastic wings and collectible coins to give out on special circumstances, according to a spokesperson. 

United hinted to Fortune that it may introduce similar cards soon. 

“We saw amazing interest in our limited-edition giveaway,” a spokesperson said. “Fans should keep their eyes out for any future cards we might have up our sleeve.”

Fortune also reached out to Spirit Airlines, Southwest Airlines, American Airlines, and JetBlue Airways for information about their own collectibles, but did not receive an immediate response.

Winging it 

Unlike its peers, Delta’s 20-year-old “customer engagement tool” is not retiring from service anytime soon.

According to Ferguson, a new batch of special-edition cards will be ready for takeoff sometime later this year.

“We can’t give the details of what it is, but it’s going to be spectacular,” he said. “Everybody’s gonna love it.”

For now, his favorite card is still the aircraft he captains—the A321 illustration from 2022—but Ferguson promises he’ll be fully stocked with the newer designs for future pilots and enthusiasts looking for their own keepsake. 

“I will have to get a sleeve of those to pass out because those are going to be gone in a second. They’re going to be fantastic.”