There's been a sea change in the costs of a European vacation. Whereas just three months ago we were all bemoaning the expense of traveling trans-Atlantic, suddenly those one-week and two-week holidays to Britain or the Continent have become far more reasonably priced. And though the situation might change in a flash, things currently are looking up.

I’ve repeatedly discussed the new strength of the U.S. dollar. As of today, the British Pound costs only $1.50 (it cost $2 to $2.05 just recently). As of today, the Euro costs only $1.25 (it had cost as much as $1.60).

But less well-realized is the sharp decline in the cost of flying the Atlantic, based primarily on the drop in oil prices to around $50 per barrel (that figure, hard to believe, was recently $140). To get some idea of the winter bargains in air transportation to Europe, you have only to scan the websites of Virgin Atlantic (a leader in offering cut-rate airfares to London) and 1800FlyEurope (the champ in low airfares to cities on the Continent).

In the case of Virgin Atlantic, they just announced a slew of one-way rates to London. Some spectacular base fares that lay the basis for an affordable London stays include:

• Boston: $213
• Chicago: $223
• Las Vegas: $320
• Los Angeles: $298
• Miami: $276
• NYC area: $198
• Orlando: $233
• San Francisco: $298
• Washington, D.C.: $213

You have to buy your tickets a minimum 7 days in advance of travel and before December 3. Most one-way fares are valid for travel through March 22, 2009, then rise modestly. Also, the fares include the fuel surcharge, but not government fees and taxes. For more information, visit Virgin Atlantic's detailed holiday fare sale page.

The same with respect to round-trip airfares, this time, between U.S. cities and various European capitals and major cities, from 1800FlyEurope. Provided you buy your tickets by November 30, and fly between now and December 10 and between January 10 and March 31, you’ll pay the round-trip rates (including fuel surcharge but not government fees and taxes) displayed on the company's Winter Airfare sale page.

Some sample base fares include:

• Atlanta to London from $439
• Boston to Barcelona from $519
• Dallas to Frankfurt from $539
• Seattle to Paris from $589
• Philadelphia to Dublin from $479

Europe, in other words, is rather reasonably priced at the moment, and will remain so as long as the dollar retains its current value and fuel stays low in price.