In a move that surprised many, Midwest Airlines and Northwest Airlines have become partners.

The two carriers, previously in no-holds-barred competition with each other, now allow members of Midwest Miles and WorldPerks to earn and redeem miles on flights operated by Northwest Airlines and Midwest, and to redeem miles on both Northwest and KLM Royal Dutch Airlines.

The new airline partners offer travel to more than 750 cities in 65 countries worldwide.

To earn miles on any scheduled Northwest flight, simply provide your Midwest Miles account number when booking your flight. An award chart for all of the new Northwest and KLM destinations will be posted on the Midwest site soon.

Not surprisingly, the new partnership means that old friends must fall by the wayside. The Midwest partnership with American Airlines ended last month.