Page 31 - Planning and Design of Airports

12 Airp o r t Pl anning

3,411
NPIAS Airports
(Of the 5,190 existing public use
airports, 65% are NPIAS)

3,356 Existing
3,254 Public Owned 55 Proposed
102 Private Owned

139 2,564 6 44
383 Commercial 270 General 3 Commercial 2 General
Primary Reliever Primary Reliever
Service Aviation Service Aviation
FIGURE 1-5 NPIAS categories.

single and twin-engine aircraft are considered basic utility airports.
Those general aviation airports that accommodate larger aircraft are
considered general utility airports.
The United States’ Federal Aviation Administration (FAA), the
governmental body with administrative oversight to the nation’s
civil aviation system, categorizes airports through its National Plan
of Integrated Airport Systems (NPIAS). As illustrated in Fig. 1-5 the
NPIAS recognizes approximately 3400 airports considered by the
FAA to be essential to civil aviation and classifies these airports by
the levels of commercial service activity within their respective stand-
ard metropolitan statistical areas (SMSAs).
Primary airports are further classified into what are known as
“hub classifications” (not to be confused with the airline “hub and
spoke” route models). The hub classifications used by the FAA are
large hub primary, medium hub primary, small hub primary, and
nonhub primary airports. Large hubs are those airports that account
for at least 1 percent of the total annual passenger enplanements in
the United States. Medium hubs account for at least 0.25 but less
than 1 percent of the total passenger enplanements. Small hubs
account for at least 0.05 percent but less than 0.25 percent, and non-
hubs account for less than 0.05 percent but at least 10,000 annual
enplaned passengers. The number of airports, by hub classification,
is illustrated in Table 1-5.
Reliever airports are airports not currently serving regular com-
mercial service but have been designated by the FAA as “general
aviation-type airports that provide relief” when necessary to com-
mercial service airports, typically by accommodating high volumes
of general aviation activity within a metropolitan area and accom-
modating commercial service operations when the nearby commer-
cial service airport is closed or otherwise cannot accommodate
normal operations. Airports are typically given “reliever” status if they