Northwest Airlines flights and fares are now booked as Delta Airlines. The two airlines merged and kept the Delta name. The Northwest Airlines name has been retired. Using our website Whatscheaper.com will now show flights that may have previously been operated by Northwest, but will now show as Delta. Whatscheaper.com is a great place to find a low fare or fare sale. Airfares constantly change and we recommend that if you find the deal you are looking for that you purchase it immediately to avoid any airfare increase!