The Louisville Regional Airport Authority released results of an economic impact study today. WFPL’s Elizabeth Kramer has more.The report says Louisville’s airports have generated nearly 56,000 jobs —or 9 percent of the area’s employment — and more than $250 million in state and local tax revenues.The gains began in the 1980s after the city decided to focus on attracting businesses working in logistics. UPS is the largest company linked with Louisville International Airport, but Greater Louisville Inc.’s president and CEO, Joe Reagan, says further gains came with efforts to attract companies in the medical field."Now companies like Amgen and Genentech and J & J [Johnson & Johnson] and other companies that you know are doing their logistics work right here from Louisville," Regan says. "In fact, Genentech, the first investment made outside of the state of California was right here in Louisville and it was right here because of this airport."Airport officials say a current $30 million effort to expand the airport should help attract even more business.Mayor Jerry Abramson helped oversee the main airport’s expansion in the 1980s, when he was mayor of the former City of Louisville. And he says it needs to expand further through a $30 million project planned to reroute part of Crittenden drive."As the planes get larger and begin to fly in both in terms of cargo as well as the future of passenger service, we’ll have the size of not only the runways," he says, "but the taxiways and the clearance area necessary to continue to grow and respond to the demand of aviation in this country for years to come."Many companies cite Louisville for its central location. Abramson says they also come because the airport has the capacity to accommodate cargo and passenger planes."There is a direct connection between economic development and access points from here on nonstop or easy access points going to headquarters or customers," he says. "And that’s why we’re always working on trying to ensure that we can grow the number of flights and the number of airlines that are flying in and out of this airport."Last year, Louisville Intentional Airport and other businesses invested nearly $523 million in capital projects there