Horizon Air announced Wednesday it is shoring up flight frequencies on some routes and discontinuing service on others -- including dropping its only Redmond-Los Angeles non-stop -- effective with its fall schedule, starting Aug. 22.

Service from Seattle to Pasco and Vancouver, and from Medford to Los Angeles, will be reduced by one flight in each market to help boost profitability on the remaining flights. Seattle-Kelowna service will be reduced by one flight in the fall, but it will be reinstated during the busier winter season.

The discontinued routes are Boise to Idaho Falls, Boise to Los Angeles, Flagstaff/Prescott to Los Angeles, Eureka/Redding to Seattle, Redmond to Los Angeles, and Sacramento to Santa Barbara.

?It's unfortunate when schedule frequency is reduced or service discontinued, and we regret any inconvenience these changes will cause,? said Dan Russo, Horizon?s vice president of marketing and communications. ?In all cases, we explored a variety of alternatives before arriving at this outcome. I would like to thank our employees who provided such great service on these routes and our customers who supported us.?

Customers holding tickets on flights affected by the changes will be re-accommodated on other flights or offered a full refund.

Horizon used to have two RDM-LAX non-stops, but dropped one in June 2008, replacing early-morning and evening flights with midday flights it called more suitable for vacation travelers. In August of that year, the airline responded to soaring fuel prices by canceling several flights, including two in and out of Central Oregon, dropping from five to four daily flights to Portland and four to three direct flights to Seattle.

Horizon currently has 57 aircraft in its fleet: 40 Bombardier Q400 turboprops and 17 Bombardier CRJ-700 jets. In conjunction with these flight reductions, Horizon plans to sublease four of its CRJ-700s to another party. Horizon is in the process of transitioning to an all-Q400 fleet for greatest efficiency, and this move will bring the airline closer to that goal.

"I don't like it - it's never good to lose direct service - but one stop through SFO is not bad - not great, but not bad," said Redmond Airport Manager Carrie Novick.

"They are selling their (regional jets), so they are shrinking the company," she said. "We will look for another airline to come in - and there are some possibilities. The passengers are still there."