PROSSER -- John Carpenter folds himself into the cramped cockpit of the Challenger II while his instructor, R.J. Blahut, does the same in the back seat.

The paper-weight wings shake with their every jostle.

Carpenter hits the ignition several times before the rear propeller catches enough momentum to whir and whine like a jet ski motor.

The pair taxi and then take off westward over the Prosser airport on another training session toward Carpenter's light sport pilot's license.

Zipping around in small planes, just for the thrill of it, is all Carpenter, a 66-year-old Richland retiree, wants out of his pilot's training. He doesn't plan long-distance travel or flying more than one passenger.

"I'm just interested in flying," he said.

His grandkids in Los Angeles? He'll book a commercial flight to visit them.

"I kind of got to the point where I needed to keep my mind active," said the retired Energy Northwest communications employee.

The light sport pilot's license, which requires about half the training and cost of a traditional private license, is the biggest demand among aspiring pilots and it's fueling a miniature boom in activity at the Prosser airport, owned by the Port of Benton.

Airport officials don't have statistics because nobody counts operations, which refers to airport takeoffs and landings. But activity is up about 50 percent in the past three years, said Cormac Thompson, the aviation development coordinator for the airport.

Most of it is due to Jackson's Flight Center opening in May 2008 as a fixed base operator, offering training, rentals and maintenance, Thompson said.

"You always see that when a school or maintenance facility opens," said Thompson.

Pilots fly in frequently to stay at the Barn Motor Inn across the street or camp at the airport's campground, perhaps visiting wineries, perhaps on business or just using it as a place to fly.

Construction crews in recent weeks have been moving the runway to the west to keep coming and going planes farther away from Wine Country Road. Eventually, they plan to apply for FAA grants to extend the runway to attract more and bigger aircraft, Thompson said.

In contrast, the Sunnyside airport, owned by the city, has no such business. Operations there are limited to a few crop duster flights; pigeons populate old hangars and 6-inch fissures criss-cross the pavement. Recognizing this, the Sunnyside City Council earlier this year passed an airport growth plan that restricts nearby development to allow for a future runway expansion in the hopes of gaining more business.

The Yakima chapter of the Experimental Aircraft Association -- a nonprofit group that advocates for amateur pilots -- has about 50 active members.

The light sport pilot license has new pilots flocking to training schools.

"It's the wave of where it's going," said Mike Robertson, principal airworthiness inspector in the FAA's Spokane flight standards district office.

The Experimental Aircraft Association worked with the FAA to develop the license to encourage more people to take up flying as a hobby. The number of active private pilots has dropped by 30 percent since 1984 in the country and dropout rates are 50 percent, according to 2005 statistics on the EAA website.

The license allows new pilots to fly small, two-seat planes with no retble landing gear, fixed-pitch propellors or instruments. It does not cover night flying.

Yakima manufacturer Cub Crafters specializes in planes that fit this category.

The license requires about 20 hours of hands-on training and about $4,000. It also does not require a medical exam like a private license does. That time can be applied later to a private license, but most new pilots are just happy for the chance to fly.

"It's a revitalization of the entry level market ... for people who are even just curious about flying," Robertson said.

Again, statistics are elusive. The FAA certifies instructors, including those who test new pilots, but does not track new license holders, Robertson said.

But Robertson agreed that Prosser's airport is becoming a small hub for the training because so few airports have base operators that offer it and few manufacturers produce the planes. Jackson's just this month opened a location that offers the training at Kennewick's Vista Field.

Blahut, the instructor and pilot at Jackson's, said he typically has two to six students at a time. They come from all over Idaho, Oregon and Eastern Washington.

Some pick away at their training little by little. Others stay in town for two weeks at a time, not leaving until they've accumulated enough hours.

But they're all in it just for fun, Blahut said.

"The key word here is sport," Blahut said. "They're out there just to fly with the hawks and pelicans and just to have some fun."

* Ross Courtney can be reached at 509-930-8798 or rcourtney@yakimaherald.com.