Wil Davis, president and one of three owners of Direct Air, spent a recent morning flying the airline's seven-seater Piper Navajo 350 on the round-trip run from Kokomo, Ind., to Detroit.

It is not the first flight he's piloted for his new business, nor will it be the last."Everyone here is dual-purpose," said Mr. Davis, speaking in the company's spartan offices in a hangar at Baer Field.

"No one says 'That's not my job.' The pilots will be handling bags,

helping passengers. Our attitude will have to be 'Whatever it takes.' "

The airline is nine years old, but has undergone a complete transformation in the six months since Mr. Davis and two partners bought it.

Before the October 1989 purchase, the airline was a subsidized operator providing Kokomo-to-Chicago service.

Since then, it has changed its route to Kokomo-Detroit, and has purchased two larger planes. One will be used on the current route, adding a stop in Fort Wayne. The other is set to begin the first service out of Gary Regional Airport since 1985, with two direct, non-stop round-trip flights a day to Pittsburgh and one round trip to Cleveland with a stop in Fort Wayne that connects to Detroit.

The start of service in Gary, Ind., was originally targeted for May 1, but Mr. Davis said that it probably will not get under way until the end of May.

He said he will probably have the equipment ready by May 15, but that he wants to give the new service the proper marketing send-off.

The King Air 200 turboprops, made by Beechcraft, have a pressurized cabin and travel about 300 mph. The flight from Gary to Pittsburgh should take about 90 minutes.

Mr. Davis, a former Navy fighter pilot who has flown almost all of his adult life, likes to compare his chances of expansion to that of Midway Airlines, which pioneered service out of Chicago's second airport 10 years ago. Since then, Midway has built itself into an international carrier.

"They started with a bigger market, but the Gary market is there in my view," said Mr. Davis. "The airlines that seem to do well are those that have an infrastructure that supports growth and expansion. I feel we have that."

But he acknowledged that it will be more difficult to attract passengers to the two turboprops his firm is buying from Mesa Airlines, a commuter line in Arizona and Air Ontario, a feeder airline for Air Canada.

"I'd like to come in with a DC-9, but I can't do it; the market is too thin," he said.

Mr. Davis said he believes the smaller equipment is the main reason that major employers in the area have not given assurances on the number of tickets they will purchase, even after years of seeking air service from Gary to Pittsburgh.

"I think the steel users wanted someone bigger, with bigger units," he said. "If I were them, I would certainly wish that a guy would come in with DC-9s. That's human nature.

"We went into this this hoping we could get the major steel users to give us the commitment, but that didn't happen, although we got assurances that some will at least give us a try," he said. "You've got to prove yourself in the marketplace. You can't put a gun to anyone's head and say they have to fly you."

Mr. Davis said he is comfortable that the market is there for the Gary airport, no matter what decisions are made by the Federal Aviation Administration about designation of a third airport for the Chicago area.

In Kokomo, Direct Air also competes with a major international airport a couple of hours away by car in Indianapolis.

And he promises that unlike Britt Airways Inc., which pulled out of Gary after a 3 1/2-month trial in the summer of 1985, he is in here for a much longer haul.

"I'm committed to Gary financially more than you can imagine," he said. ''We've never discussed, 'If we're not successful in 60 days, we're out of here.' This is a total entrepreneurial risk, trying to establish the service. If it was easy, someone else would have done it already. We're hungry enough that we're not going to give up."