The beginning of the 21st Century has produced many significant developments in the history of Philadelphia International Airport. Since 2001, the opening of two new terminals has nearly doubled the size of the Airport complex from 1.4 million to 2.4 million square feet and expanded the number of boarding gates by 85% from 55 to 120. Unprecedented demand for air travel, spurred by low-fare competition, has steadily increased passenger traffic to 31.8 million in 2008.