Midwest Airlines (AMEX:MEH) has signed a Memorandum of Understanding with Northwest Airlines to form a strategic codeshare partnership between the two carriers. The new partnership will greatly expand the networks of both carriers by adding 250 city pairs and more than 1,000 new flight options for customers.

Passengers can book their entire flight on a single ticket, with all segments earning mileage credit in either the Midwest Miles or Northwest WorldPerks frequent flyer programs.

The agreement with Northwest is the next step in the continuing roll-out of Midwest’s wide-ranging 2007 growth plan. Along with other key elements of the plan, this is expected to enhance the value of the company for shareholders by providing significant revenue impact as a result of offering customers more ways to easily reach their favorite cities.

Northwest routes that will include the Midwest Airlines “YX” code are destinations beyond Northwest’s hubs at Detroit, Minneapolis/St. Paul and Memphis throughout the United States and Canada. Midwest will also place its code on Northwest flights from Indianapolis, a Northwest focus city. Additionally, Midwest’s code will appear on a number of Northwest-operated flights to Hawaii and Alaska.

Routes operated by Midwest Airlines that will carry the “NW” Northwest code are flights that connect at Midwest’s Milwaukee and Kansas City hubs, as well as Omaha — a Midwest focus city. Northwest will also codeshare on Midwest Airlines-operated flights between Milwaukee and Kansas City to Atlanta, Boston, Hartford, Los Angeles and San Francisco that connect to the Northwest/KLM trans-Atlantic network and trans-Pacific network.

The codeshare partnership is expected to begin this summer, pending execution of definitive agreements. Complete details on codeshare destinations and fares will be announced at a later date.

Midwest Airlines features jet service throughout the United States, including Milwaukee’s most daily nonstop flights and best schedule to major destinations. Catering to business travelers and discerning leisure travelers, the airline earned its reputation as “The best care in the air” by providing passengers with impeccable service and onboard amenities at competitive fares. Both Skyway Airlines, Inc. — a wholly owned subsidiary of Midwest Airlines — and SkyWest Airlines, Inc. operate as Midwest Connect and offer service to and connections through Midwest Airlines’ hubs. Together, the airlines offer service to 51 cities. More information is available at http://www.midwestairlines.com/.