The Alamo and National brands have been listed on Orbitz since 2001. Enterprise Holdings -- which acquired Alamo and National in 2007 -- had been in negotiations to add its flagship brand to the Orbitz site when it was informed of Orbitz's decision to remove both National and Alamo, and accept only Enterprise. 

"Through our many decades of serving customers in this industry, we have learned it is difficult to fully meet the changing transportation needs of consumers with only one brand," said Nicholson. "As a result, following our purchase of Alamo and National almost four years ago, we consciously decided to maintain three separate rental car brands, each with a unique service offering."  

Alamo is a leisure brand known for offering discounts to deal-shopping customers. National is a brand preferred by business travelers and other frequent renters. Enterprise -- the largest car rental brand in North America -- is available both on and off airport and has the largest network of locations in the industry. Across all three brands, Enterprise Holdings and its regional subsidiaries own and operate nearly one million vehicles, which constitute the world's largest fleet of passenger vehicles. 

"We realize our role as the industry leader comes with a responsibility to keep our product affordable and to aggressively advocate for the rights of consumers," Nicholson said. "For example, we lead our industry in the fight to curtail excise taxes that unfairly single out rental car customers. Today, rental car taxes account for as much as 20 percent of the cost in many markets, placing our industry's customers among the highest taxed in the United States."