By TOM DAYKIN

The union that represents pilots at AirTran Airways has concerns about the carrier's new marketing agreement with SkyWest Airlines at Milwaukee's Mitchell International Airport.

AirTran announced Wednesday that SkyWest will offer new regional jet service between Milwaukee and six destinations: Pittsburgh; St. Louis; Akron/Canton, Ohio; Indianapolis; Des Moines, Iowa; and Omaha, Neb.

Tickets for the flights will be sold though AirTran's reservation system, and revenue will be shared between the two airlines.

Once the SkyWest flights begin, AirTran will end its service from Milwaukee to Pittsburgh, St. Louis and Indianapolis, and will shift those Boeing 717 jets to other routes, including new Milwaukee-Dallas service.

AirTran says the arrangement with SkyWest is a cost-effective way to build its Milwaukee hub.

But the Air Line Pilots Association says the partnership amounts to outsourcing work.