ASPEN – High winds from the cold front that moved into Aspen on Sunday have combined with a construction project to cause the cancellations of several United Express flights this week.

David Ulane, assistant aviation director of the Aspen/Pitkin County Airport, said the ongoing runway extension project has shortened the runway from 7,000 feet to 6,500 feet temporarily, making it difficult for United to fly its CRJ-700 jet into Aspen during windy weather.

Sunday’s cold front is the culprit behind the high winds, which tend to blow during late morning and early afternoon, he said. The winds have not affected Frontier Airlines, which flies a Q400 turboprop that can handle Aspen’s shorter runway, he said. General aviation also is unaffected.

SkyWest Airlines partners with United Express to handle the Aspen flights. SkyWest representative Marissa Snow said at least 15 incoming and outbound flights were affected Monday, Tuesday and Wednesday. In some cases, flights into Aspen were diverted to the Eagle airport or returned all the way to Denver. The airline paid for buses to take passengers from Eagle into Aspen, she said.

To accommodate the extension project, the runway soon will be shortened further, to 6,000 feet for a few days. When that occurs, United Express won’t be able to fly into Aspen at all, airport officials have said.

The shortening of the runway is necessary to provide a construction safety zone at the south end of the airport, where 1,000 feet is to be added to the existing runway. Once complete, the runway will be 8,000 feet long.