Nonstop flight route between Fort Sill, Oklahoma, United States and Cahokia, Illinois (near St. Louis), United States:
Departure Airport:

Arrival Airport:

Distance from FSI to CPS:
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- About this route
- FSI Airport Information
- CPS Airport Information
- Facts about FSI
- Facts about CPS
- Map of Nearest Airports to FSI
- List of Nearest Airports to FSI
- Map of Furthest Airports from FSI
- List of Furthest Airports from FSI
- Map of Nearest Airports to CPS
- List of Nearest Airports to CPS
- Map of Furthest Airports from CPS
- List of Furthest Airports from CPS
About this route:
A direct, nonstop flight between Henry Post Army Airfield (FSI), Fort Sill, Oklahoma, United States and St. Louis Downtown Airport (CPS), Cahokia, Illinois (near St. Louis), United States would travel a Great Circle distance of 531 miles (or 855 kilometers).
A Great Circle is the shortest distance between 2 points on a sphere. Because most world maps are flat (but the Earth is round), the route of the shortest distance between 2 points on the Earth will often appear curved when viewed on a flat map, especially for long distances. If you were to simply draw a straight line on a flat map and measure a very long distance, it would likely be much further than if you were to lay a string between those two points on a globe. Because of the relatively short distance between Henry Post Army Airfield and St. Louis Downtown Airport, the route shown on this map most likely still appears to be a straight line.
Departure Airport Information:
IATA / ICAO Codes: | FSI / KFSI |
Airport Name: | Henry Post Army Airfield |
Location: | Fort Sill, Oklahoma, United States |
GPS Coordinates: | 34°38'58"N by 98°24'7"W |
Operator/Owner: | U.S. Army ATCA-ASO |
Airport Type: | Military |
Elevation: | 1189 feet (362 meters) |
# of Runways: | 1 |
View all routes: | Routes from FSI |
More Information: | FSI Maps & Info |
Arrival Airport Information:
IATA / ICAO Codes: | CPS / KCPS |
Airport Name: | St. Louis Downtown Airport |
Location: | Cahokia, Illinois (near St. Louis), United States |
GPS Coordinates: | 38°34'14"N by 90°9'21"W |
Area Served: | Greater St. Louis |
Operator/Owner: | Bi-State Development Agency |
Airport Type: | Public |
Elevation: | 413 feet (126 meters) |
# of Runways: | 3 |
View all routes: | Routes from CPS |
More Information: | CPS Maps & Info |
Facts about Henry Post Army Airfield (FSI):
- Henry Post Army Airfield (FSI) currently has only 1 runway.
- Air Service/Corps units assigned to Post Field between 1919 and 1941
- Although the Signal corps had been supplying Observation aircraft for the United States Army Field Artillery School since 1915.
- Fort Sill has embarked on a new plan to support the museum in providing a more dynamic learning experience for the 200,000 military and civilian personnel who visit each year.
- The furthest airport from Henry Post Army Airfield (FSI) is Sir Gaëtan Duval Airport (RRG), which is located 10,920 miles (17,575 kilometers) away in Rodrigues Island, Mauritius.
- The closest airport to Henry Post Army Airfield (FSI) is Lawton–Fort Sill Regional Airport (LAW), which is located only 6 miles (9 kilometers) S of FSI.
- Henry Post Army Airfield was the first home of all Army Aviation Training after World War II before moving to Fort Rucker, Alabama in 1954.
- The Army will continue to operate and maintain a precision approach radar at Fort Sill's Henry Post Field for the foreseeable future.
Facts about St. Louis Downtown Airport (CPS):
- The closest airport to St. Louis Downtown Airport (CPS) is Lambert–St. Louis International Airport (STL), which is located only 16 miles (27 kilometers) NW of CPS.
- The furthest airport from St. Louis Downtown Airport (CPS) is Margaret River Airport (MGV), which is located 10,998 miles (17,700 kilometers) away in Margaret River, Western Australia, Australia.
- St. Louis Downtown Airport (CPS) has 3 runways.
- Because of St. Louis Downtown Airport's relatively low elevation of 413 feet, planes can take off or land at St. Louis Downtown Airport at a lower air speed than at airports located at a higher elevation. This is because the air density is higher closer to sea level than it would otherwise be at higher elevations.
- The two survivors out of the airport's original four hangars, Hangar 1 and Hangar 2, are listed on the National Register of Historic Places.