when to go?

1. Go in winter, spring or fall. By avoiding the summer peak season, which many carriers define as late May through the first week of September, you'll save hundreds on airfare. And because theaters, museums and many other pastimes are indoors, you'll still have fun.

In a recent spot-check of flights online, the lowest LAX-London round-trip fare was $1, 200, including taxes and fees, for nonstops in summer, compared with less than $700 for travel into March. Expect to pay $50 to $200 more in April and early May, said Brian Clewer, owner of the Continental Travel Shop, an air consolidator and travel agency in Santa Monica.

To snag the best price or even to get a seat, book way ahead. Most fliers are buying international tickets more than three months before departing, said Amy Ziff, editor at large for Travelocity.com.

Don't count on fares dropping in 2008, experts told me, even though more airlines will fly to London. That's because Heathrow and Gatwick have limited slots; oil prices remain high; and fuel surcharges of up to $220, along with taxes and fees, already add hundreds to each transatlantic ticket.