ATLANTA - Some U.S. airlines have added a $10 surcharge to fares for travel dates around the Thanksgiving and New Year's holidays, according to, a site that compares prices for flights.

The service said Delta Air Lines Inc and its Northwest unit and US Airways Group Inc on Friday joined UAL Corp's United in matching the move started by AMR Corp's American Airlines earlier this week.

The $10 miscellaneous surcharge applies for three travel dates: Nov. 29, the Sunday after Thanksgiving, and Jan. 2 and 3, said.

All three dates are peak holiday travel days; the Sunday after Thanksgiving competes with the Wednesday before the holiday for the title, 'busiest air travel day of the year,' Chief Executive Rick Seaney said in an email.

American spokesman Tim Smith said in an email that holiday travel periods have always had times of peaks and valleys in customer demand. He added American's $10 surcharge applied each way for domestic travel on the three days.

Airlines have sought new sources of revenue over the past year as they seek to counter declining passenger traffic. (Reporting by Karen Jacobs, editing by Leslie Gevirtz)