national plan of integrated airport systems march 2005 2 principles for the system safe efficient flexible expandable permanent compatible with surrounding communities developed in concert improvements to air traffic control support objectives defense emergency readiness and postal delivery accessible affordable contribute economy international competitiveness 3 us airports by ownership & use 19 576 total 5 280 open public 14 296 closed 4 177 owned 388 npias 344 existing 233 111 private 44 proposed 383 primary 127 commercial service ercial 278 reliever 556 general aviation 36 1 103 privately 27 73 97 secretary transportation
