RDU Airport will add a new dot to its map of nonstop destinations in April, when Frontier Airlines returns to the Triangle market with a new flight to Trenton-Mercer Airport (TTN) in central New Jersey.

The Trenton airport is midway between the Newark and Philadelphia airports, not far from Princeton University. Denver-based Frontier also is adding flights from Trenton to Columbus, Detroit, Atlanta and Chicago-Midway.

The TTN-RDU flight, starting April 8, will run every day of the week except Saturday. Frontier says is offering introductory one-way fares as low as $29.

Frontier Airlines is ending the only nonstop service between Raleigh-Durham International Airport and Milwaukee next month and ceasing operations at RDU.

Frontier, a subsidiary of Indianapolis-based Republic Airways, will stop its two daily departures from RDU on June 6.

The airline resumed the nonstop flights in April 2010, when it was known as Midwest Airlines.

While travelers can still reach Milwaukee from RDU, it will involve the extra hassle of changing planes in another city. RDU officials and economic developers are eager for more airlines add nonstop flights, which can be a powerful recruiting tool for this region.

"We are always disappointed when an airline ceases operations," RDU officials wrote in a prepared statement. "However, we have a very strong market, and we have learned that when demand is strong, airlines will step in to meet it."

Midwest Airlines, which resumed its nonstop service between Raleigh-Durham International Airport and Milwaukee this month, will soon see its name disappear.

The carrier's parent, Republic Airways, announced today that it plans to phase out the Midwest brand in favor of Frontier Airlines, another subsidiary. Denver-based Frontier is known for "spokesanimals" painted on the tails of its planes.

Republic CEO Bryan Bedford told the Associated Press that travelers associated the Frontier name with low fares, while Midwest was seen as more of a high-price airline. The Midwest brand will be dropped by Oct. 2011.

"Maintaining two brands is just not cost-effective for us," he said.

Republic bought Midwest in July and Frontier in October. The company announced in January that it would pick between the two names.

Midwest, which will continue to provide free chocolate-chip cookies under its new name, restarted its service at RDU on April 1. It had stopped the service for a second time in September 2008 as the economy tanked.

As part of the name change, Republic will add a new animal logo to its fleet: A badger to honor Wisconsin's state animal. No word on whether the company will add North Carolina's gray squirrel.