By Alana Wise

(Reuters) – More than 45 million passengers will take to the skies on U.S. airlines this holiday season, Airlines for America projected on Thursday, up 3.5 percent from holiday travel last year.

During the 21-day stretch from Dec. 16 through Jan. 5, between 1.8 million and 2.4 million passengers daily will fly globally aboard U.S. carriers, according to the Washington-based trade group.

“An improving economy and reduced airfares remain the driving force behind the growth seen in air travel,” Airlines for America Chief Economist John Heimlich said in a statement.

“As we saw over Thanksgiving, U.S. airlines are well positioned to handle the increase in passengers expected this holiday season,” he added.

U.S. carriers got a trial run at the upcoming travel rush during the 12 days of Thanksgiving travel, the trade group said.

During Thanksgiving travel, airlines had a completion factor of 99.4 percent, a percentage of flights an airline completes without cancellation, and an on-time arrival rate of 84.5 percent, the industry body said.

Airlines for America said it expects the most congested travel days to fall on Dec. 22 and Dec. 23, while fewer travelers are expected on Christmas Eve, Christmas Day, New Year’s Eve and New Year’s Day.

(Reporting by Alana Wise; Additional reporting by Jeffrey Dastin; Editing by Alan Crosby)