<item>1. Existing airports, heliports, seaplane bases, etc. recorded with FAA. Includes military airports with joint civil and military use. Includes U.S. outlying areas. Airport-type definitions: Public--publicly owned and under control of a public agency; private--owned by a private individual or corporation. May or may not be open for public use.
<item>2. Fiscal year data. Does not include System Planning Grants. Includes U.S. outlying areas. 1970-1982 data are obligated Federal funds for the Airport Development Aid Program. 1983-1989 data are appropriated Federal funds under the Airport and Airway Improvement Act of 1982.
<item>3. Registered aircraft that flew one or more hours during the year.
<item>4. Includes helicopters.
<item>5. Includes autogyros; excludes air carrier helicopters.
<item>6. Includes all active pilots. An active pilot is one with a pilot certificate and a valid medical certificate. Also includes pilots who hold only a helicopter, glider, or lighter-than-air certificate, not shown separately.
<item>7. Includes dispatchers, flight navigators and engineers, and ground technicians--mechanics, parachute riggers, and ground instructors.
<item>8. No medical examinations are required, therefore, data represents all certificates on record and includes retired or otherwise inactive technicians.
<item>9. Includes all air traffic control specialists (staff positions, managers, supervisors, and for 1970-1986 traffic management coordinators, not shown separately) and air traffic assistants. Beginning in 1987, includes full-time, permanent only.
<item>10. Serving in-flight service stations, towers, and centers.
<item>11. Prior to 1987, included in total air traffic control specialists.
<item>12. Source:1970 & 1975, U.S. Bureau of Mines; 1980-1986 FAA General Aviation Activity and Avionics Survey.
<item>13. Includes kerosene-type and naphtha-type jet fuels.
</list>
<p>Source: Except as noted, U.S. Federal Aviation Administration, includes data from U.S. Dept. of Transportation.
