If you’re planning to take a Northwest flight between now and Dec. 31, it would be well worth your while to book your trip online at www.nwa.com. And if you’re not planning a trip, you might want to reconsider.

WorldPerks members who book online for the first time before the Dec. 31 promotion deadline will earn 5,000 bonus miles. But, you say, I’ve already used the Northwest Web site to book a trip, so how does this promotion benefit me? Glad you asked. All subsequent bookings will earn members an additional 2,500 bonus miles.

Miles will be credited after qualifying travel is complete. Neither offer is valid with any of the following reservations: CyberSavers, E-Biz Perks or Award Travel — not that miles come to mind when you think of CyberSavers. Northwest WorldPerks miles must be earned on the qualifying itinerary to be eligible for the bonus – so you can forget earning any partner miles.