# /07

# hapter 1: System Composition

TheUnited States accounts for approximately 40 percent ofall commercial aviation and 50 percent ofallgeneral aviation activity in the world. An extensive system ofalmost 20,000 airports throughout the U.S. has been developed to support this activity. A primary purpose ofthe NPIAS is toidentify the airports that are important to national transportation needs and, therefore, eligible to receive grants under the AlP. The NPIAS includes 65 percent ofthe 5,261 U.S. airports that are opentothe public (see Figure 4). The plan contains all primary and commercial service airports; all general aviation airports designated as reliever airports by FAA, and selected general aviation airports. 

### Figure4: Numberof Existing and Proposed Airports 

### by Ownership and Use (July 2006)

382 2 Primary Primary
135 6 Commercial Commercial Service Service
274 4 Reliever Reliever
2.573 55 General General Aviation Aviation

1 National Plan of Integrated Airport Systems (2007·2011){ dfor airtravel has grown inthe last two years with regional and low-cost carriers 13growing hfaster than the legacy carriers." The rapid growth ofsome low-cost carriers has added to the cial difficulties of some legacy carriers. Legacy carriers are reducing operating costs replacing e-body and larger narrow-body aircraft with smaller narrow-body and regional jet aircraft, and reducing fares in markets served by low-cost carriers. The use of smaller narrow-body aircraft owsthe air carrier to better match the number ofseats to the number ofpassengers. In some ases,airlines have also downsized or closed hubs, redirecting capacity to their core or primary hubs.



### se ofReliever and Secondary Airports edistribution oftraffic among airports to make more efficient use of facilities is another measure tbatcanbe used to reduce delays. Reliever airports have been identified and improved in metropolitan areas to provide general aviation pilots an attractive alternative to congested commercial service airports. Large metropolitan areas usually have a system ofreliever airports, one ormore ofwhich can accommodate corporate jet aircraft and others designed for use by smaller, propeller-driven aircraft. Relievers have been very successful at relocating general aviation activity fromcongested airports. As aresult, general aviation activity at congested airports is a small and decreasing percentage oftotal operations (one percent of operations at Atlanta Hartsfield and Seattle; twopercent ofoperations atJohn F. Kennedy Airport and Chicago O'Hare; three percent of operations at LaGuardia Airport, Newark, and Los Angeles).
Another factor that helps to limit delay is the ability of carriers to introduce service to outlying, suburban airports, using them to relieve congestion atthe principal airport. This regional approach isparticularly effective in very large cities that are the origin or destination point for many trips by air,such as Boston, Washington, San Francisco, Los Angeles, and New York. Low-cost carriers havebegun serving alternative airports in metropolitan areas and providing competition to carriers at theprincipal airport. Traffic has increased significantly atthe alternative airports that attracted lowcostcarriers. Examples include Boston (Manchester and Providence); Washington (BaltimoreWashington); San Francisco (Oakland, San Jose, and Sacramento); Miami (Ft. Lauderdale); Chicago (Midway); and Los Angeles (Long Beach, Burbank, Ontario, and Orange County).


## SAFETY
TheU.S. has the largest, most complex, and safest aviation system in the world. Figure 9 below shows accidents per 100,000 flight hours for general aviation and large air carriers. The key component ofthe aviation system and resulting safety record is the airport. Although itis rare that theairport is determined to be acause ofan aircraft accident, itmay be cited as acontributing factor thatoften affects the severity ofthe accident. Through AlP, funds are provided to airport operators forcapital improvements to their facilities. AUsuch improvements must meet standards adopted by FAA. Use ofuniform standards at airports throughout the system promotes safety.

13AmericanTrans Air, America WestAirlines, Air'Iran Airways, Frontier Airlines, JetBlue Airways, Sun Country Airlines,Southwest Airlines, and SpiritAirlines 14AlaskaAirlines, American Airlines, Continental Airlines, Delta Airlines, Northwest Airlines, United Airlines, and US Airways

National Plan of Integrated Airport Systems (2007-2011) 23