| Roy Otten Memorial Airfield | Versailles | VRS | 2 |
| Ruston Regional Airport | Ruston | RSN · KRSN | 1 |
| Safford Regional Airport | Safford | SAD · KSAD | 2 |
| Saginaw Seaplane Base | Saginaw Bay | SGW | 1 |
| Salem–Leckrone Airport | Salem | SLO · KSLO | 1 |
| Salida Airport - Harriet Alexander Field | Salida | SLT · KANK | 1 |
| Salina Gunnison Airport | Salina | SBO | 1 |
| Salton Sea Airport | Salton City | SAS · KSAS | 1 |
| Sampson County Airport | Clinton | CTZ · KCTZ | 1 |
| Samuels Field | Bardstown | BRY · KBRY | 1 |
| San Carlos Apache Airport | Globe | GLB | 1 |
| San Gabriel Valley Airport | El Monte | EMT · KEMT | 1 |
| Sanderson Field | Shelton | SHN · KSHN | 1 |
| Sandpoint Airport | Sandpoint | KSZT | 1 |
| Sanford Seacoast Regional Airport | Sanford | SFM · KSFM | 2 |
| Santa Cruz Island Airport | Santa Cruz Island | SZN · KSZN | 1 |
| Santa Paula Airport | Santa Paula | SZP · KSZP | 2 |
| Santa Ynez Airport | Santa Ynez | SQA · KIZA | 1 |
| Schenck Field | Clarinda | ICL · KICL | 2 |
| Schoolcraft County Airport | Manistique | ISQ · KISQ | 2 |
| Scottsdale Airport | Scottsdale | SCF · KSDL | 1 |
| Scribner State Airport | Scribner | SCB · KSCB | 2 |
| Searcy Municipal Airport | Searcy | SRC · KSRC | 1 |
| Sebring Regional Airport | Sebring | SEF · KSEF | 2 |
| Sedalia Memorial Airport | Sedalia | DMO · KDMO | 2 |
| Sedona Airport | Sedona | SDX · KSEZ | 1 |
| Selfs Airport | Marks | MMS · KMMS | 1 |
| Sequim Valley Airport | Sequim | SQV | 2 |
| Shafter Airport - Minter Field | Shafter | MIT · KMIT | 2 |
| Shageluk Airport | Shageluk | SHX · PAHX | 2 |
| Shalz Field | Colby | CBK · KCBK | 3 |
| Sharp County Regional Airport | Ash Flat | CKK · KCVK | 1 |
| Shawnee Regional Airport | Shawnee | SNL · KSNL | 1 |
| Sheboygan County Memorial Airport | Sheboygan | SBM · KSBM | 2 |
| Sheep Mountain Airport | Sheep Mountain | SMU · PASP | 1 |
| Shelby Airport | Shelby | SBX · KSBX | 2 |
| Sher-Wood Airport | Plentywood | PWD · KPWD | 3 |
| Sherman Army Air Field | Fort Leavenworth | FLV · KFLV | 1 |
| Shively Field | Saratoga | SAA · KSAA | 1 |
| Shreveport Downtown Airport | Shreveport | DTN · KDTN | 2 |
| Sidney Municipal Airport | Sidney | SXY | 1 |
| Sikeston Memorial Municipal Airport | Sikeston | SIK · KSIK | 1 |
| Silver Comet Field at Paulding Northwest Atlanta Airport | Dallas | KPUJ | 1 |
| Siskiyou County Airport | Montague | SIY · KSIY | 1 |
| Skagit Regional Airport | Burlington | MVW · KBVS | 2 |
| Skwentna Airport | Skwentna | SKW · PASW | 1 |
| Skylark Field | Killeen | ILE · KILE | 1 |
| Skypark Airport | Bountiful | BTF · KBTF | 1 |
| Slayton Municipal Airport | Slayton | NSL · KDVP | 1 |
| Smith Field | Siloam Springs | SLG · KSLG | 1 |
| Smith Field | Fort Wayne | SMD · KSMD | 2 |
| Socorro Municipal Airport | Socorro | ONM · KONM | 2 |
| Solomon State Field | Solomon | SOL | 1 |
| South Big Horn County Airport | Greybull | GEY · KGEY | 2 |
| South Jersey Regional Airport | Lumberton | LLY · KVAY | 1 |
| Southern California Logistics Airport | Victorville | VCV · KVCV | 2 |
| Southern Seaplane Airport | Belle Chasse | BCS | 2 |
| Southern Wisconsin Regional Airport | Janesville | JVL · KJVL | 3 |
| Southwest Michigan Regional Airport | Benton Harbor | BEH · KBEH | 2 |
| Southwest Minnesota Regional Airport - Marshall/Ryan Field | Marshall | MML · KMML | 2 |
| Sparta Community Airport - Hunter Field | Sparta | SAR · KSAR | 2 |
| Sparta Fort McCoy Airport | Sparta | CMY · KCMY | 2 |
| Spartanburg Downtown Memorial Airport | Spartanburg | SPA · KSPA | 1 |
| Spence Airport | Moultrie | MUL · KMUL | 1 |
| Spencer Municipal Airport | Spencer | SPW · KSPW | 2 |
| Spirit Lake Municipal Airport | Okoboji | RTL | 1 |
| Springdale Municipal Airport | Springdale | SPZ · KASG | 1 |
| St Clair County Airport | Pell City | PLR · KPLR | 1 |
| St Clair County International Airport | Port Huron | PHN · KPHN | 2 |
| St Johns Industrial Air Park | St Johns | SJN · KSJN | 2 |
| St Landry Parish Ahart Field | Opelousas | OPL · KOPL | 2 |
| St Louis Downtown Airport | Cahokia/St Louis | CPS · KCPS | 3 |
| St Marys Municipal Airport | St Marys | STQ · KOYM | 1 |
| St. Mary's County Regional Airport | California | LTW | 1 |
| Stafford Regional Airport | Fredericksburg | KRMN | 1 |
| Stan Stamper Municipal Airport | Hugo | HUJ · KHHW | 1 |
| Stanton Airfield | Dennison | SYN · KSYN | 2 |
| Statesboro Bulloch County Airport | Statesboro | TBR · KTBR | 2 |
| Statesville Regional Airport | Statesville | SVH · KSVH | 1 |
| Steamboat Bay Seaplane Base | Steamboat Bay | WSB | 1 |
| Steamboat Springs Bob Adams Field | Steamboat Springs | SBS · KSBS | 1 |
| Stephens County Airport | Breckenridge | BKD · KBKD | 3 |
| Stephenville Clark Regional Airport | Stephenville | SEP · KSEP | 1 |
| Sterling Municipal Airport | Sterling | STK · KSTK | 2 |
| Stevens Field | Pagosa Springs | PGO · KPSO | 1 |
| Stevens Point Municipal Airport | Stevens Point | STE · KSTE | 2 |
| Storm Lake Municipal Airport | Storm Lake | SLB · KSLB | 3 |
| Strother Field | Winfield / Arkansas City | WLD · KWLD | 2 |
| Stroud Municipal Airport | Stroud | SUD · KSUD | 1 |
| Stuttgart Municipal Airport / Carl Humphrey Field | Stuttgart | SGT · KSGT | 2 |
| Sullivan County Airport | Sullivan | SIV · KSIV | 1 |
| Sullivan County International Airport | Monticello | MSV · KMSV | 1 |
| Sulphur Springs Municipal Airport | Sulphur Springs | SLR · KSLR | 1 |
| Sumers Airpark | Glenwood Springs | GWS · KGWS | 1 |
| Summit Airport | Cantwell | UMM · PAST | 1 |
| Sumter Airport | Sumter | SUM · KSMS | 2 |
| Sunriver Airport | Sunriver | SUO | 1 |
| Susanville Municipal Airport | Susanville | SVE · KSVE | 2 |
| Sylvester Airport | Sylvester | SYV · KSYV | 1 |
| Taku Lodge Seaplane Base | Taku Lodge | TKL · PTFK | 1 |