tensile-frame construction
bent frame
- national air issues coordinating committee
- national air issues steering committee
- national air mail week
- national air mobility system
- national air-monitoring audit
- national air monitoring station
- national air monitoring system
- national air museum
- national air navigation services company
- national air photo library
- national air pollution background network
- national air pollution background program
- national air pollution control administration
- national air pollution control technical advisory committee
- national air pollution surveillance network
- national airport grant information system
- national airport system plan
- national air quality information archive
- national air quality management programme
- national air quality objectives
- national air quality standard
- national air quality strategy
- national air race
- national air-racing group
- national airspace data interchange network