With Refer-A-Friend, invite up to 5 friends to fly Northwest Airlines and you can earn up to 20,000 Bonus Miles and your friends can earn unlimited Bonus Miles.

Here’s how it works:
Register for Refer-A-Friend.
We’ll send you a confirmation e-mail that you can forward to up to 5 friends. The e-mail will invite them to enroll as your “Friends”.
Friends must be WorldPerks members. (It’s easy to join and membership is free.)
Friends may not have earned WorldPerks miles for travel since January 1, 2005.
The first time each enrolled friend completes one of the activities listed below, you’ll earn the associated Bonus Miles. If all friends complete each of the activities, you’ll earn a total of 20,000 Bonus Miles. (Activities must be completed by May 31, 2006.)
Each time one of your friends completes one of the activities listed below, they’ll also earn the associated Bonus Miles. There’s no limit to the Bonus Miles they can earn during the promotion period!