BILLINGS - The future of Big Sky Airlines in Montana and four other Western states is in a troubling holding pattern: Either a buyer is found soon or the regional carrier may shut down.

Big Sky Airlines is based in Billings and flies 13 Beechcraft 19-passenger 1900D aircraft to 26 cities and towns in 10 states. But an expansion to Boston Logan International Airport in April to fly connecting flights for Delta Airlines may have proved fatal.

Big Sky President Fred deLeeuw said that nine months after buying three airplanes to serve the East Coast markets, the airline was losing enough money and that investors are calling it quits.

On Wednesday, Big Sky announced it is terminating all Boston and Cincinnati, Ohio, flights effective Jan. 7. The aircraft will be sold and up to 140 jobs will be cut, mainly in Boston, New York and Kentucky.

Also on Jan. 7, Big Sky will cut another 30 flights out of 47 in Montana, Wyoming, Idaho, Colorado and Washington state, DeLeeuw said.

Unless a buyer is found, service to Sheridan and Denver will also stop at midnight Jan. 7, according to company documents. Flights to Essential Air Service locations in Montana could stop as soon as Feb. 1.

EAS is a program of the U.S. Department of Transportation that offers air carriers federal subsidies to fly to small cities and towns.

"In the next few months, Big Sky Airlines may cease to exist," one company document said. "We are working on a definitive severance policy for all noncontract employees."

Under federal rules, a carrier cannot eliminate some EAS routes and keep others, so Big Sky needs to trim flights on both coasts.

Big Sky employees can continue to travel on Delta until Jan. 8, according to the documents.

DeLeeuw painted a more positive picture, saying Big Sky is talking to two or three potential buyers.

"We're going to keep flying in Montana until such time as we can transition over to another carrier," deLeeuw said.

He said a sale could happen by early February. Great Lakes Aviation based in Cheyenne has been listed as a potential buyer, but deLeeuw wouldn't confirm that.

Jon Austin's Minneapolis-based company represents MAIR Holdings Inc., also of Minneapolis, which has been the holding company for Big Sky Transportation Co. since 2002. Big Sky Transportation does business under the name Big Sky Airlines.

Austin said he didn't want to predict a shutdown.

"They are trying to actively find someone to take it over," Austin said of Big Sky.

Since buying Big Sky in December 2002, MAIR has lost more than $22 million, according to financial statements.

Also in 2002, MAIR purchased Mesaba Aviation out of Minnesota, which went into bankruptcy reorganization in 2005 and is now operating as a Northwest Airlines' subsidiary.

The MAIR holding company is liquidating its only two assets: Big Sky Airlines and some cash.

"Once Big Sky is sold and the cash distributed, MAIR will be effectively out of business," Austin said.

Paul Foley, president and chief executive officer of MAIR, said Thursday that the Big Sky operations aren't sustainable.

Meanwhile, deLeeuw said the Essential Air Service money will increase substantially in March.

"Montana would be profitable then," he said.

Big Sky flies 86 daily flights in the U.S. and started flying in Montana out of Billings in 1978.

When asked how Big Sky could move into the East Coast market and fail in just nine months, deLeeuw said the airline ran into poor customer demand and two other obstacles.

"I think fuel went up $1 a gallon," he said. "We were doing OK until the weather really hit us in October and November. Today is the sixth storm grounding in Boston when nothing comes in, except your costs keep climbing."

Big Sky flies connecting flights to Alaska Airlines, Horizon Air, Northwest Airlines and US Air.

"Our people are doing a fabulous job providing safe and reliable service until we transition off to another company," DeLeeuw said.