DULUTH — The U.S. Air Force Thunderbirds, known for flying F-16s in tight formation and in choreographed loops, rolls and inversions, return to Duluth for the first time since 2018.

The Duluth Airshow is Saturday and Sunday at Duluth International Airport — a showcase of performers from the Air Force, trick-flying civilians in colorful planes and a static display of historic and current aircraft.

The Thunderbirds were scheduled to star in 2020, an event that was canceled because of COVID-19. Last year, with the Blue Angels headlining, the airshow drew a record audience of about 75,000, according to president Ryan Kern.

"We virtually had more people then we've ever seen — the pent-up demand from the pandemic," he said.

He's not expecting to top that this year, instead predicting a number closer to normal — about 50,000 people, between those who officially pass through the gates and those who find free vantage points near the airport.

The Thunderbirds' squadron has eight pilots, six who do demonstrations, and perform more than 70 shows a season.

The Thunderbirds fly the same planes used by the locally based Minnesota Air National Guard's 148th Fighter Wing. The stunt planes are retired from combat, painted and aren't able to drop bombs or shoot missiles — though they generate smoke, which is used in some of the maneuvers the audience will see.

"It's like taking a car and stripping it down and making something that goes in a parade," said Maj. Jodi Grayson, a member of the 148th Fighter Wing and media coordinator for the airshow. "It looks the same, but it has different features."

F-16s are no longer being built, Grayson said. It's the Air Force's F-35s — bigger planes with a beefier sound — that are replacing them. They, too, will be on hand at the show.

The Air Force's F-35 Lightning II Demonstration Team, announced last week, is a late addition to the lineup after a cancellation in the United Kingdom, according to Kern. The F-35s were last seen at the 2019 airshow. Maj. Kristin "Beo" Wolfe, an F-35 demo pilot, is one of three women to be featured at the airshow — more than ever before. The lineup also includes Maj.r Lauren Schlichting, who is with the Thunderbirds, and Jessy Panzer, who can put a decorated Pitts Special biplane into a flat spin, leaving a trail of curlicue smoke, as seen in videos from past airshows.

Other highlights include the Yak 110, a single plane that combines two Yak 55s and a GE J85 jet engine, and, at ground level, a Hot Streak II — a modified '57 Chevy pickup with twin jet engines that can travel more than 350 miles per hour and shoots flames.

The airshow is seemingly one of the city's biggest annual tourist events — alongside Grandma's Marathon, which drew about 21,000 runners in June. A 2018 economic impact study of the marathon found that an estimated 2.2 people accompanied every runner, according to public relations director Zach Schneider. That would mean more than 45,000 spectators for the race that runs along North Shore from near Two Harbors to Canal Park.

The last time airshow officials conducted an economic impact study was more than a decade ago, Kern said. At that time, it was a $10 million economic benefit to the city. He estimates that this has nearly doubled in the past 10 years.

According to airshow officials, 75 percent of the spectators come from the Twin Cities metro area. As of mid-week, there was still lodging available — though it was expensive. Visitors can stay in a bunk at the Hostel du Nord in downtown Duluth for just more than $175 a night to a suite at Mont du Lac Resort near Superior, Wis., for more than $1,300.

Adult general admission tickets for the airshow start at $25 for a one-day pass and are available online or at any Menards store in Minnesota.