DALLAS (AP) -- No surprise here -- holiday travel will cost more again this year.

Most of the largest U.S. airlines have increased a surcharge for travel on the busiest travel days to $20 each way, up from $10.

The surcharges apply to a large number of flights within the U.S. on more than a dozen peak days around holidays including Thanksgiving, Christmas and New Year's.

Tom Parsons, who runs the discount travel site Bestfares.com, says Delta, American, United, US Airways and Northwest all boosted their surcharge on some routes.

Tim Smith, a spokesman for Fort Worth-based American Airlines, says it's basically supply and demand.

Parsons says the increases are part of a clear trend in airline pricing, given airline downsizing, increased fuel costs and financial losses.

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