In all his 80 years, Horizon Air founder Milton Kuolt never entered a room quietly.

He'd throw open the door, step in wearing cowboy boots and a duster coat, and howl his signature greeting: "Yo!"

"That was his thing. 'Yo.' He'd just yell it, no matter where he was," said Bill Peare, Mr. Kuolt's longtime friend and a vice president at Horizon. "In a meeting, at a party, on the golf course. He was a character, for sure."

Mr. Kuolt, who died Friday at Swedish Medical Center in Seattle, started Horizon Air, one of the nation's first regional carriers, in 1981. He sold the company to Alaska Airlines in 1988. Mr. Kuolt began his long career at Boeing, and later started Thousand Trails, a private, timeshare-style campground company, in the early 1970s.

In his many roles at different companies, Mr. Kuolt was known for his formidable work ethic, his sense of humor and his unflappable allegiance to all of his employees, regardless of their rank.

"Milt didn't care if you were a baggage handler or in the boardroom. He was concerned about everybody on his team," said Bill Endicott, who worked for Mr. Kuolt at Thousand Trails and Horizon, and later wrote "Remember the Magic: The Story of Horizon Air."

According to one of the stories in Endicott's book, Mr. Kuolt once overheard a man being rude to one of his employees at the ticket counter. "He leaned over and told him he wasn't welcome to fly on Horizon Air anymore," Endicott said. "Milt said, 'Nobody treats my employees like that. I don't care if you have to ride to Sun Valley on a horse!' "