Roughly 3,300 of the public use airports across the U.S. have been determined by the FAA to be significant to national air transportation. They form a national airport system intended to provide convenient access to air transportation and support important national functions, such as defense, emergency readiness, and postal delivery. These airports are eligible to receive federal Airport Improvement Program (AIP) grants to help fund their capital development. They might also collect local passenger facility charges (PFCs) from passengers. This report discusses (1) how much national system airports received in funding for capital development projects from 2009 to 2013 and from which sources; (2) the estimated costs of airports' planned capital development from 2015 through 2019; (3) how past funding levels compare with planned development costs; and (4) how changes to AIP funding and the maximum allowable PFC might affect airport funding. Tables and figures. This is a print on demand report.