Frontier Airlines will cut daily departures from Milwaukee by 44 percent to drop unprofitable flights as parent Republic Airways Holdings Inc. prepares to sell or spin off the carrier.

Frontier will end non-stop service to six cities by mid-April, as departures from Milwaukee are reduced from 32 to 18 a day, Lindsey Carpenter, a spokeswoman, said in a telephone interview on Friday.

Republic is close to naming an adviser to help divest Frontier, which it bought out of bankruptcy in 2009. Frontier faced competition in Milwaukee from Southwest Airlines Co., the biggest low-fare carrier. The city had served as a Frontier hub since Republic bought Midwest Airlines in 2009 and combined the two carriers under the Frontier name.

“We’ve been incurring significant losses on our flights out of Milwaukee,” Carpenter said. “We can’t continue to do that if we want to stay a viable airline.”

Frontier is still assessing how many employees will be affected by the changes and hopes to offer them other jobs with the airline, she said. Midwest’s Milwaukee departures peaked at 150 a day in 2007.

The carrier no longer will fly non-stop from Milwaukee to Dallas-Fort Worth, Kansas City, Philadelphia, Phoenix, Newark and Grand Rapids, Mich. The cuts come as the airline expands flights from its main base in Denver.

Republic fell 2.2 percent to $5.87 at market close on Friday. The shares have risen 71 percent since Jan. 1.