Travel December 25 & 26 for cheapest airfare deals

Passengers are reflected in a Christmas tree decoration at the airport in the western German city of Duesseldorf

If you're traveling from the US over the Christmas period, Monday, December 19 departures and Friday, December 30 returns are the dates to avoid, according to new research from Travelocity.

The travel booking site become the latest to release its predictions of holiday airfares December 6, saying that a US domestic trip on those dates would work out to be the most expensive, at an average of $496 return.

That compares to an average airfare over the period of $406 for domestic flights and $918 for international flights.

Travelocity said that the cheapest flights to be found at the moment involved flying out on Christmas Day (December 25) and returning Boxing Day (December 26), which added up to an average of $262 return.

Other cheaper options involve leaving Christmas Day and returning December 27/28, although a Christmas Eve (December 24) outwards journey and a December 27 return still worked out at a fairly reasonable $358.

"Travelers departing on Christmas Eve or Christmas Day, will find their tickets to be below this year’s average airfare ($17 - $144 less than average)," said the firm.

"In comparison, travelers will spend the most when departing the Monday before Christmas, December 19, and returning the Friday after, December 30 ($90 more than average)."

According to FareCompare, the average cost of holiday travel this year has risen by around $40 compared to the same period in 2010, thanks to cuts in capacity.

It warned earlier this year that American, Delta and United/Continental are also imposing flight surcharges of between $20-$40 for the busiest days, including December 22, 23, 26 and January 2.