The Washington region’s two major airports contributed more than $18 billion to the local economy in 2005, according to figures released today by the Metropolitan Washington Airports Authority. Dulles International Airport and Ronald Reagan Washington National Airport — which collectively employ about 28,500 people — generated the billion-dollar figure through both direct airport spending and indirect visitor spending.

Much of the 2005 figure was related to the ongoing expansion of Dulles. In 2005, the Airports Authority spent $464 million on the project, which included completion of a new air traffic control tower and additional gateways linked to the main terminal. Those projects employed 2,600 construction workers. An environmental impact study looking at the effects of a fourth and fifth runway was also completed in December.