In a move to get back at United Airlines for a similar offer, Northwest is offering double elite miles for all flights through October 9th. Whlie the United offer was targeted to select travelers in the upper Midwest, everyone is eligible for the Northwest offer (registration is required, though). This is nearly an unprecedented offer, as double elite deals generally require fares in expensive fare classes. Not so here—even cheap flights count. I don’t expect other airlines to match, so if you’re close to Elite on Northwest, this would be a good time for a little mileage run.