We're seeing some excellent deals on Delta and United flights to London for winter/late summer travel.

Travel dates range from January through late March, and again from September onward. You'll find the lowest fares are for weekday travel, with slightly higher fares for weekends.

This sale is unadvertised, meaning these fares could vanish at any time. Should something catch your eye, better book quickly.

Fares include:

Fort Lauderdale to London $563 round-trip

Portland to London $572 round-trip, nonstop

Minneapolis to London $573 round-trip, nonstop

Philadelphia to London $579 round-trip, nonstop

Washington DC to London $594 round-trip

Detroit to London $662 round-trip, nonstop

Atlanta to London $663 round-trip, nonstop