http://biz.yahoo.com/bw/070812/20070812005073.html?.v=1

NW is, in fact, a passive investor in the buyout of YX

from the release:

NWA, which is providing financing to facilitate the transaction, will not participate in the management or control of Midwest should TPG acquire Midwest. The previously announced codeshare agreement between NWA and Midwest Airlines will remain in place and the two airlines will explore cost reduction activities such as joint fuel purchasing.

Northwest has briefed its union leadership on the transaction. The investment contemplated is consistent with all of NWA's union obligations.

OP: You may want to change the title. As stated, ATA is not involved in any of this. It is AirTran. Air Midwest is a part of Mesa Airlines that provides, for the most part, B1900 regional service for US Airways. The company being taken over is Midwest Airlines.