| MDH | KMDH | Southern Illinois Airport | Carbondale | |
| BCS | - | Southern Sea Plane Base | Belle Chasse | |
| - | - | Southland | Sulphur | |
| - | - | Spadaro | East Moriches | |
| - | - | Spanaway | Spanaway | |
| - | - | Spanish Fork-Springville | Spanish Fork | |
| - | - | Spanish Peaks | Walsenburg | |
| - | - | Spanish Springs | Reno | |
| - | - | Sparta | Sparta | |
| SAR | KSAR | Sparta Community Airport | Sparta | |
| SPA | KSPA | Spartanburg Downtown Memorial Airport | Spartanburg | |
| - | - | Spaulding | Susanville | |
| - | - | Spearman Municipal | Spearman | |
| - | - | Speedway Airport | Indianapolis | |
| MUL | KMUL | Spence Airport | Moultrie | |
| - | - | Spencer | Spencer | |
| SPW | KSPW | Spencer Municipal Airport | Spencer | |
| - | - | Spencerport | Spencerport | |
| - | - | Spicewood | Spicewood | |
| RTL | - | Spirit Lake Airport | Spirit Lake | |
| OIL | - | Splane Memorial Airport | Oil City | |
| - | - | Sportsman | Newberg | |
| - | - | Spotted Bear Usfs | Spotted Bear | |
| - | - | Spring Hill | Sterling | |
| - | - | Springer Municipal | Springer | |
| - | - | Springerville Babbitt | Springerville | |
| SGH | KSGH | Springfield Airport | Springfield | |
| - | - | Springfield Municipal | Springfield | |
| - | - | Springfield Municipal | Springfield | |
| - | - | Springfield Municipal | Springfield | |
| - | - | Springfield Robertson Co | Springfield | |
| - | KSPH | Springhill | Springhill | |
| - | - | Springview Municipal | Springview | |
| - | - | Spruce Creek | Daytona Beach | |
| - | - | St Charles Airport | St Charles | |
| PHN | KPHN | St Clair County International Airport | Port Huron | |
| - | - | St Elmo | St Elmo | |
| - | - | St George | St George | |
| - | - | St George Island | Apalachicola | |
| - | - | St Helen | St Helen | |
| - | - | St Ignatius | St Ignatius | |
| - | KJYG | St James Municipal | St James | |
| - | - | St John The Baptist Parish | Reserve | |
| - | - | St Labre Mission | Ashland | |
| OPL | KOPL | St Landry Parish Airport | Opelousas | |
| - | - | St Louis Metro East Shafer Field | St Jacob | |
| - | - | St Maries Municipal | St Maries | |
| - | - | St Marys | St Marys | |
| XSM | - | St Marys Airport | Saint Marys | |
| - | - | St Thomas Municipal | St Thomas | |