As passengers departed the Delta flight from New York to Des Moines, a crowd was forming.

At least a dozen men and women were gathering by the gate. Some appeared to know each other. Others were introducing themselves and shaking hands for the first time. They were different ages, genders and races, but they all had one thing in common: They were all decked out in campaign gear.

The group assembling in the airport were just a small number of about 1,000 "Barnstormers for Pete" descending on Iowa on Halloween for a long weekend. Their visit was not organized in coordination with the South Bend mayor's campaign. Instead, the Barnstormers for Pete found each other and planned the trip online.

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Kat Sosnick was working at her home computer back in February when she came across a random article about the Midwestern mayor exploring a bid for President.

"I think what really drew me to him more than anything is I've long felt that Washington is out of touch with us small-potato constituents," said Sosnick, a New York City resident. She ended up going to Facebook and joining what was then the only unofficial Buttigieg group. After a couple of weeks, she reached out to ask if she could be one of the administrators on the page.

"Barnstormers for Pete" gather in New York City before flying to Des Moines on October 31, 2019 CBS News

"While I was involved in this one group, I threw this idea of here's a candidate who really has no name ID and doesn't have the national political infrastructure that his peers have, how can we help the electorate become more aware of this candidate," said Sosnick. "The only way we could do it given our limited resources is to use digital platforms."

Today, there are about 350 different Facebook pages dedicated to supporting his bid for the presidency. There are online groups with names like Women for Buttigieg, African Americans for Buttigieg, Iowans for Buttigieg and even Republicans for Buttigieg. Members of these groups share their experiences, bond over frustrations with the current political climate, and let people know about local organizing events in their communities.

In August, Sosnick ended up meeting fellow supporters Donna Pappalardo, Lisa Connelly and Abby Dart in person for the first time at a youth event she hosted at her home. They also met Julie Parker, originally from Indiana but currently living in Seattle, thanks to social media. Their group bonded over ways they could channel their energy for Buttigieg, despite not living in any of the early states.

At the time, Sosnick had already been invited to the caucuses by another Buttigieg supporter based in Iowa. When she mentioned it, Dart, who had traveled to Iowa around the same time for then-candidate Barack Obama in 2007, suggested they go earlier for the Liberty and Justice Celebration, a major Democratic event in Iowa that occurred earlier this month. And with that, the idea of a Barnstormers for Pete road trip was born.

"We were talking about the Barnstormers road tripping like the Deadheads used to do," Pappalardo said with a laugh.

Within three days of the group sending out an invite through their digital network, 400 people signed up for the trip. In 3 weeks, it was 700 people from 49 states. By the time they were heading to Iowa, that number had grown to more than a thousand. With the late addition of a supporter from Delaware, participants now came from all 50 states, with 160 coming from California alone.

"It almost seems shocking, which it kind of was," said Connelly. "But at the same time it wasn't at all because I knew interacting with the people that I was on the internet, there was so much passion that it just seemed very natural to for people to say 'yes of course I'll do it.'"

Parker, who was a Sanders supporter in 2016, ended up renting a trailer to haul large sets of decorated letters spelling out Buttigieg's name from Seattle to Des Moines. It took her and a friend three days to complete the trip.

Ariana Wyndham, a DACA recipient who helps with the Barnstormers social media, says she and her husband drove more than 11 hours from Warren, Ohio to Des Moines. Along the way, they picked up other Buttigieg fans they had met online from Chicago and Cleveland.

A supporter of South Bend Mayor Pete Buttigieg holds a sign in Iowa. CBS News

"I can say that I'm confident in [Buttigieg's] values and who he is to come up with some policies and plans that are really going to change things not even just for me but my family and everybody around us in our community," Wyndham said. "It was a huge undertaking for everybody. It was just a stretch for a lot of us. But it was just amazing."

The Barnstormers started their weekend Thursday night with a Halloween party where they bagged candy to send to U.S. troops. Chasten Buttigieg, the mayor's husband, ended up "party crashing." So did the candidate's mother, in-laws and campaign manager.

On Friday morning, they held "PeteUps" at coffee shops across Des Moines, so people based in different regions could meet fellow supporters near them. In the afternoon, they ended up attending Buttigieg's pre-dinner rally and marching with him and local supporters to the Wells Fargo arena, where the Liberty and Justice dinner was held.

Due to the large number in attendance, many couldn't get tickets to the actual celebration, so they watched the speeches from an overflow room at a nearby hotel. Some were handed tickets at the last minute from Beto O'Rourke supporters after the former Texas congressman dropped out of the race only hours before.

On Saturday morning, the Barnstormers for Pete were bundled up bright and early for an organized power walk in downtown Des Moines. It ended up turning into a rally at a park, where they shared their stories of support for the candidate and learned choreography for a flash mob set to "High Hopes," the mayor's walk-out song.

Barnstormers also received canvasing training from the campaign nearby. While Sosnick reiterated they were not there as a canvass group, about 150 Barnstormers headed off into the local community that day to knock on hundreds of doors and collect commit cards.

"Barnstormers for Pete" gather before canvassing for South Bend Mayor Pete Buttigieg in Iowa. CBS News

Out-of-state supporters flocking to Iowa is nothing new. President Jimmy Carter deployed the so-called Peanut Brigade from Georgia ahead of the 1976 caucuses. Walter Mondale's "Fritz Blitzers" came to the state from Minnesota in 1984. However, not all volunteer efforts yielded successful results. In 2004, Howard Dean's "Stormers" came from all over the country thanks in part to the use of the internet. They became known as the "orange hats" thanks to the headgear they wore knocking on doors.

"A lot of the stuff now that's accepted normal organizing politics over the internet in 2003, 2004 was completely unheard of," said Dean's campaign manager, Joe Trippi. "The fact that all these people found Howard Dean over the internet and decided to come to Iowa, the other campaigns were actually kind of using it to scare people."

Trippi pointed out that while the criticism at the time was effective, Obama perfected online organizing in 2008, and it's now mainstream practice. "I think this is totally a different time."

It's too early to tell how effective the Barnstormers for Pete will be. But a Tuesday poll from Monmouth University did find that the once-obscure mayor was now leading the rest of the Democratic field in Iowa.

Barnstormers for Pete are already eyeing their next road trip to New Hampshire, this time working with the campaign. After that, the Barnstormers have plans to travel to Nevada and South Carolina, with some members committing to visiting all four early states.

The Barnstormers want to make it back to Iowa in time for the caucuses on February 3, which means they don't have much time to organize their trips elsewhere. Online efforts are already underway to recruit more than 300 vehicles to help Iowans get to caucus locations.

"I hope that the level of energy continues and grows and this snowball effect is getting bigger and bigger," said Pappalardo.