| S | South, Southern Latitude |
| SALS | Short Approach Lighting System |
| SALSF | Short Approach Light System with Sequenced Flashing Lights |
| SAM | South America (ICAO Region) |
| SAP | Soon as Possible |
| SAR | Search and Rescue |
| SAT | South Atlantic (ICAO Region) |
| SAT | Saturday |
| SATCPM | Satellite voice air-ground calling |
| SAWRS | Supplementary Aviation Weather Reporting Station |
| SB | South Bound |
| SCA | Southern Control Area |
| SCATANA | Security Control of Air Traffic and Air Navigation Aids |
| SCIA | Simultaneous Converging Instrument |
| SCOB | Scattered Clouds or Better Approaches |
| SDF | Simplified Directional Facility |
| SE | south-east |
| SEB | South-Eastbound |
| sec / SEC | Seconds |
| SECT | Sector; Section |
| SELCAL | Selective Calling System |
| SEP | September |
| SERV/SER | Service |
| SER | Stop End of Runway |
| SFC | Surface |
| SFL | Sequenced Flashing Lights |
| SHF
| Super High Frequency (3000 to 30000 MHz) SID Standard Instrument Departure |
| SID | Standard Instrument Departure |
| SIF | Selective Identification Feature |
| SIG | Signature |
| SIMUL | Simultaneous or simultaneously |
| SIWIL | Single Isolated Wheel Load |
| SKED / Skd | Schedule(d) |
| SLAP | Slot Allocation Procedure |
| SLP | Speed Limit Point |
| SILW | Slow |
| SM | Statute Mile(s) |
| SMB | Side Marker Board |
| SIVIC | Surface Movement Control |
| SMGCS | Surface Movement Guidance and Control System |
| SMR | Surface Movement Radar |
| SNOWTAM
| A special series Notam notifying the presence or removal of hazardous conditions due to snow, ice, slush or standing water associated with snow, slush and ice on the Movement area, by means of a specific format |
| SOC | Start Of Climb |
| SODALS | Simplified Omni-directional Approach Lighting System |
| SOTA | Shannon Oceanic Transition Area |
| SPAR | French Light Precision Approach Radar |
| SPEC | Special |
| SPL | Supplementary Flight Plan Message |
| SQ | Square |
| SR | Sunrise |
| SRA | Special Rules Area |
| SRA | Surveillance Radar Approach |
| SRE | Surveillance Radar Equipment |
| SRG | Short Range |
| SIRR | Search and Rescue Region |
| SRY | Secondary |
| SRZ | Special Rules Zone |
| SRZ | Surveillance Radar Zone |
| SS | Sunset |
| SS | Sliding Scale |
| SSALF | Simplified Short Approach Light System with Sequenced Flashing Lights |
| SALR
| Simplified Short Approach Lighting System with Runway Alignment Indicator Lights |
| SSALS | Simplified Short Approach Lighting System |
| SSB | Single Side Band |
| SSE | South South East |
| SSM | Standard Specifications Manual |
| SSR | Secondary Surveillance Radar |
| SST | Supersonic Transport |
| SSTP | side-step |
| SSW | South South West |
| STA | Straight-in Approach |
| STAR | Standard Terminal Arrival Route |
| STD
| Indication of an altimeter set to 29.92" Hg or 1013.2 Mb without temperature correction |
| STD /Std | Standard |
| ST-IN | Straight-in |
| STN | Station |
| STOL | Short Take-off and Landing |
| SUBJ | Subject to |
| SUN | Sunday |
| SUPPS | Regional Supplementary Procedures |
| SVC | Service Message |
| SVCBI | Serviceable |
| SW | south-west |
| SW | Single Wheel Landing Gear |
| SWAP | Severe Weather Avoidance Plan |
| SWY | Stopway |
