Courtney Hedlund scurried around the Cirrus SR-20, wiping down the wings, the fuselage, the tail and eventually the entire body of the single-engine plane she and her co-pilot had just landed at Lawrence Municipal Airport.

Even the smashed remains of a bug could make a tenth of a second difference when it comes to the speed of an airplane, the 24-year-old Kalamazoo, Mich., woman said.

And speed, knowing how to make the wind work for you and doing well at visual-reference navigation are the keys to determining the winner in the all-women Air Race Classic, now in its 30th year.

Even a tenth of a second can make a difference in an air race, Hedlund said.

“It could be close,” she said.

Hedlund and Leslie Ann Treppa, also of Kalamazoo, are flight instructors at Western Michigan University, which also owns the plane.

They landed about 3:30 p.m. Wednesday, several hours after the first plane landed about 9:30 a.m.

But Hedlund thought she and Treppa, also 24, were doing well since taking off Tuesday at the start of the race that began in Mesa, Ariz.

“The flight was good,” Hedlund said as Treppa obtained the latest weather report and got refreshed inside the air terminal. “It’s been pretty smooth. Well, a little bit bumpy here and there.”

Lawrence is the sixth stop for about 40 planes participating in the race that ends in Menominee, Mich. Planes landing in Lawrence arrived from the previous refueling stop in Ada, Okla.

While strong southerly winds helped the planes move faster, the 90-degree weather at ground level also was making it hot in the air.

“We have a lot of windows, so it’s kind of like a greenhouse,” Hedlund said of conditions inside the cramped plane. “We have one vent for each of us.”

There have been no mechanical problems, Hedlund said. Though all planes must have landed at one of the stops by dusk, she was hopeful that she and Treppa might make it all the way to Menominee.

“We might be done tonight (Wednesday). Maybe not,” she said. “It was exciting to pass the other planes along the way.”

Hedlund and Treppa were flying in their first Air Classic.

The first plane to land in Lawrence was piloted by Gretchen Jahn, Kerrville, Texas, and Carol Foy, Spicewood, Texas. They were flying a single-engine Mooney M20R.

The planes make a first pass over the airport before landing, so timers using atomic clocks can record their arrival. All of the planes have handicap speed, and they try to obtain a ground speed that is faster than the handicap speed, said Dorothy Dickerhoof, the race’s stop chairwoman in Lawrence.

The scoring of the race is such that the pilots don’t know how well they’ve done until the last plane has landed at the final stop. The first to land isn’t necessarily the winner.

Several planes and their crews were expected to stay over in Lawrence.

Joe Minard, of Cheney, sat outside the air terminal and waited for the plane piloted by his wife, Trish Minard, and copilot Karen Monteith, of Wichita, to land. He thought they were about 30 minutes away in their Cessna 182. Minard was doing work in the Lawrence area and decided to meet his wife at the airport.

“I really didn’t expect her here until tomorrow (Thursday), but there’s that strong south wind,” he said.

More of the planes are expected to arrive in Lawrence today before the race wraps up, probably on Friday.