CHARLOTTE, N.C. — Thousands of people celebrated Charlotte Douglas International Airport Monday, some of whom didn’t know why until they passed by the event. Senator Thom Tillis, U.S. Representatives Alma Adams and Dan Bishop joined state and local leaders to take part in a celebration of American Airlines being a part of the airport for 40 years. It started back in 1982 when the doors to a new terminal at the airport welcomed Piedmont Airlines as a regional carrier. Several mergers later, America’s Charlotte hub has grown to become the second-largest across its global network connecting CLT to the world, while serving as an economic engine for the Carolinas.