According to
http://skymilesoffers.delta.com/airline_partners.php
Midwest Airlines:
Mileage may be earned on all Midwest-operated flights. The effective date of mileage credit is October 1, 2009. Earn 100% of actual miles flown (500 minimum). Earn 100% Medallion Qualifying Miles for fare classes: Y, B, H, V, Q, K, W, M, T, R. O. P. Earn Medallion Qualifying Segments for fare classes: Y, B, H, V, Q, K, W, M, T, R, O, P.
Only issue is that Midwest no longer operates their own flights at all. They use Republic or Frontier or other codeshares.
If I book an LAX-MKE flight on Midwest YX752, an A319 operated by Frontier, would I earn appropriate DL miles and MQMs?