OSHKOSH, Wis. — Steve Wittman made a pitch.

The airport he ran here had two runways, one that ran east-west and another north-south.

Equally important in his 1969 proposal to Paul Poberezny was the land that surrounded the air strips. It would provide ample room to park planes and campers from around the globe and ultimately create an internationally heralded event that is the gold standard for those fascinated with wings, aeronautics and the people pushing aviation forward.

AirVenture, the Experimental Aircraft Association's fly-in convention, has drawn astronauts, decorated fighter pilots, Hollywood stars, engineers and just about every type of aircraft imaginable over the years. The agreement between Wittman and Poberezny, EAA's founder, also transformed the city of Oshkosh and the region.

This year, the fly-in is marking 50 years in Oshkosh with 600,000 people expected to celebrate all things aviation. The seven-day event that opens Monday generates about $170 million of economic impact in a five-county area, according to a 2017 study by UW-Oshkosh and commissioned by the EAA.

"It really puts it in perspective that this is really a big, important event that can't be underestimated. There's just so much impact," said Amy Albright, executive director of the Oshkosh Convention & Visitors Bureau. "For the people that come here, it's their Disney World."

The EAA grounds and Wittman Regional Airport are expecting to park 5,000 of the estimated 10,000 airplanes that come to the region during AirVenture with the remaining planes parked at surrounding airports. Wittman has 8,000 landings and the EAA grounds host 40,000 campers on 12,000 campsites, 800 of which are equipped with water and electricity. There are more than 5,000 volunteers, 800 exhibitors, 1,100 bathrooms and four new permanent buildings that each have 50 showers.

Off the 1,500-acre grounds, hotels are booked, restaurants in the area have some of their biggest weeks of the year and retailers compare it to Christmas. Those who live in the area boost their own incomes by renting out rooms or even whole houses to EAA visitors, the Wisconsin State Journal reported .

Dorms at UW-Oshkosh, Marion University in Fond du lac and Ripon College are rented out, and Valley Christian School on Oshkosh's north side becomes a lodge as it converts offices and classrooms into bedrooms and offers meal plans and shuttle service to the EAA grounds. At the YMCA, the air-conditioned indoor soccer field is turned into a campground as guests, who pay between $40 and $60 a night, are allowed to set up freestanding tents.

Meanwhile, the airspace above Wisconsin becomes a buzz of activity. AirVenture holds nine airshows in seven days while later this week, formations of planes making their way to Oshkosh will be spotted throughout the state. For example, flocks of Cherokees are scheduled to depart Saturday from Waupaca, Mooneys will take off from Madison and a squadron of Cessnas will arrive from Juneau. On Sunday, scores of Cirrus aircraft will depart from Janesville.

Smaller groups of fighter planes and bombers from World War II are common sights as are biplanes and thousands of smaller, home-built planes by some of the EAA's 220,000 members. They are flown not only from around the country but from around the world, with some swapping out seats for gas tanks in order to make the trip over vast stretches of ocean.

"From an aviation event (perspective), it's the biggest in the world, relative to general aviation and recreational aviation. So if that is one of your hobbies and interests, this is the place. There's nothing even remotely close and that's continued to grow and build," said Jack Pelton, who retired from Cessna and was named the EAA's CEO in 2015. "It has a uniqueness that even if you're not an airplane geek, it's a fun enough activity that you want to participate. It's just a wonderful place to be and I think that's what sustains this thing."

The EAA was founded in Poberezny's Milwaukee basement in early 1953 as a local club for those who built and restored their own planes. The first fly-in was in September of that year at Wright-Curtiss Field (now Timmerman Airport) and dubbed the Milwaukee Air Pageant. It drew about 20 planes and 150 people and quickly outgrew the airport. In 1959, Poberezny moved the event to the Rockford Municipal Airport in northern Illinois where the event established itself with diverse aircraft, airshows and international visitors.

During the convention, Rockford was declared the "sport plane capital of the world," governors from Illinois and Wisconsin were frequent visitors and the economic impact to the area in the 1960s was between $250,000 and $500,000, according to the Rockford Register-Republic, the city's daily newspaper.

But Poberezny became miffed when there was little support from local groups to provide visitor information and direct crowds. Poberezny told the newspaper in 1967 that he wanted the event to stay in Rockford, but by 1969, the airport's manager, Robert Selfridge, demanded that no camping be held at the airport if there were aerobatic demonstrations. The EAA also needed more space at the airport to accommodate its growing crowds.

"Poberezny said the decision to locate elsewhere was made because relations with Selfridge had worsened in the last several years and EAA officials felt they were no longer welcome and not wanted in Rockford," the newspaper wrote in 1969.

EAA officials looked at a few other sites around the Midwest, but it was the offer from Wittman that was the most attractive. The offer set in motion an aeronautical, economic and social boom in Oshkosh, where the Ho-Chunk lived for centuries and where, in the 1800s, sawmills lined the Fox River, many of which provided lumber to rebuild Chicago after the great fire of 1871.

OshKosh B'gosh was founded in 1895, Oshkosh Corp., formerly Oshkosh Truck, manufactures specialty and military vehicles, and Lake Winnebago offers the city boundless recreational opportunities, including sturgeon spearing each February. The city is also home to other major tourism events like the country music festival Big Country USA and Rock USA. This weekend features the Waupaca Boatride Volleyball Tournament, which started last week with 1,800 teams from around the country, while Lifefest, one of the largest Christian music festivals in the country, was expected to draw nearly 20,000 people to the Winnebago County fairgrounds over the weekend.

The EAA, which opened its museum in 1983, has helped bolster tourism year-round and drawn other major events to the region, like next month's International Pathfinder Camporee. The event, one of the largest Adventist youth events in the world, is expected to draw more than 50,000 people from more than 100 countries to the EAA grounds over five days.

But the fly-in convention is the most anticipated event of the year.

In 2005, Rockford created AirFest, one of the Midwest's largest air shows, but the last show was in 2015. The city is now touting the table tennis Olympic trials for North America, a mural festival, Tough Mudder and a basketball event that celebrates Rockford native Fred VanVleet, who won an NBA title this year with the Toronto Raptors. In 2006, Cheap Trick named an album after Rockford, its hometown.

"I think we feel very fortunate and embrace (AirVenture), but we don't take it for granted," said Albright of the convention and visitors bureau. "AirVenture put us on an international map. For a town of 65,000, that really says something. We would look very different without them."

The first fly-in in 1970 drew around 100,000 people but by 1976 attendance had tripled. Three years later, despite fuel shortages for both planes and automobiles, attendance rose to 400,000 people. That growth continued in the 1980s as attendance reached 800,000 and included a visit in 1989 by the SR-71 Blackbird spy plane. Attendance hit a peak of an estimated 850,000 in 1994, but in 2005 had dropped to 700,000. EAA officials say attendance has been relatively stable at about 600,000 over the last several years and their ability to accurately count the crowds has vastly improved with electronic people counters, scanning wrist bands and tracking ticket sales.

The challenge to maintaining the event is continually upgrading facilities to meet the needs of modern day campers and visitors, said Pelton. It ranges from better campsites to more food options at concession stands, more portable bathrooms and showers and improved traffic flow. A study is underway this year to determine how to better move people throughout the grounds.

"It's grown so big," Pelton said. "Those are the things you have to constantly work on."

An AP Member Exchange shared by the Wisconsin State Journal.