KEY: N = data are nonexistent; NPIAS = National Plan of Integrated Airport Systems.
NOTES: NPIAS airports are defined in box 2-B in
chapter two; they include the 513 commercial service airports. Only percentage data are readily
available. The number of existing
NSPIAS airports vary from year to year.
In 2004, there were a total of 3,356 NPIAS airports.
Data for 1994-1996 are non-existent.
SOURCES: 1997-2003—U.S. Department of Transportation (USDOT), Research and Innovative Technology Administration, Bureau of Transportation Statistics, National Transportation Statistics 2004, table 1-24, available at http://www.bts.gov/, as of January 2005. 2004—USDOT, Federal Aviation Administration, National Planning Division, personal communication, February 2005.