Today marked the first phase of full NW/DL reservation system integration.

Effective today (Jan. 9, 2010), Northwest flights will be replaced with Delta flights in schedules and availability displays from September 5, 2010 and beyond.

As part of that first phase of integration, all existing Northwest PNRs which include a flight with a departure date of September 5, 2010 or later were migrated to the DL system today... meaning that if you have a trip booked via NWA (ticket issued on 012 stock / booked at nwa.com) for travel after 9/5/2010, your reservation is now in the DL system.