| 2501 | SDS | United Kingdom Civil Aviation Authority | | | ICAO1 |
| 2502 | SDS | SUNDANCE STAGE LINES INC A CALIFORN | | | SCAC4 |
| 2503 | SDSB | SCULLY DISTRIBUTION SERVICES INC (L | | | SCAC4 |
| 2504 | SDSC | S & D SERVICES INC | | | SCAC4 |
| 2505 | SDSD | STEED STANDARD TRANSPORT LIMITED | | | SCAC4 |
| 2506 | SDSE | SURE DELIVERY SERVICE, INC | | | SCAC1 |
| 2507 | SDSH | SEAYS DELIVERY SERVICE AIR FREIGHT | | | SCAC4 |
| 2508 | SDSI | SELEX DELIVERY SYSTEMS INC | | | SCAC4 |
| 2509 | SDSJ | SCOTIAN DISTRIBUTION SERVICES LIMIT | | | SCAC4 |
| 2510 | SDSN | S D S LOGISTICS SERVICES | | | SCAC4 |
| 2511 | SDSO | SDS DE MEXICO SA DE CV | | | SCAC4 |
| 2512 | SDSR | STELLAR DISTRIBUTION SERVICES INC | | | SCAC4 |
| 2513 | SDSU | SOO LINE RAILROAD | | | PWRC |
| 2514 | SDSU | Soo Line Railroad (Canadia Pacific Railway) | | | RSRV |
| 2515 | SDSV | SAYER DELIVERY SERVICE INC | | | SCAC4 |
| 2516 | SDSW | SHEPAUG DISTRIBUTION SERVICES LLC | | | SCAC4 |
| 2517 | SDT | Terrain Sdp, S.A. | Callsign: Terrain, | E | AVCODES |
| 2518 | SDT | San Diego Transit | | US-CA | TRAFFIC |
| 2519 | SDTB | S D T | | | SCAC4 |
| 2520 | SDTC | STAR DIAMOND TOOLS INC | | | SCAC4 |
| 2521 | SDTG | SHERIDAN BROKERAGE LLC | | | SCAC4 |
| 2522 | SDTI | SAN DIEGO TROLLEY, INC. | | | PWRC |
| 2523 | SDTL | SODREL TRUCK LINES INC | | | SCAC4 |
| 2524 | SDTM | SUDDATH RELOCATION SYSTEMS OF MELBO | | | SCAC4 |
| 2525 | SDTQ | SEND TRUCKING COMPANY | | | SCAC4 |
| 2526 | SDTR | SERVICIOS DE TRANSPORTES RAPIDOS S | | | SCAC4 |
| 2527 | SDTS | SCHNEIDER NATIONAL CARRIERS INC (DE | | | SCAC4 |
| 2528 | SDTT | S & D TRUCKING GROUP INC | | | SCAC4 |
| 2529 | SDTV | SHER-DEL TRANSFER & RELOCATION SERV | | | SCAC4 |
| 2530 | SDTZ | (GTW) RETIRED 10-19-93 ATP | | | PWRC |
| 2531 | SDU | Westair Commuter Airlines, Inc. / United Express | Designator OE recalled by IATA | USA | AVCODES |
| 2532 | SDU | Westair Commuter Airlines, Inc. / United Express | IATA: OE, Designator OE recalled by IATA | USA | AVCODES |
| 2533 | SDU | Sud Airlines | Callsign: Sud Lines, Ceased operations. | F | AVCODES |
| 2534 | SDU | Dumont Aircraft Charter, LLC d/b/a Dumont Aviation | Callsign: Santos, | USA | AVCODES |
| 2535 | SDU | Sud Airlines | | | ICAO1 |
| 2536 | SDUC | SUPPLY DOCK CARRIERS INCORPORATED | | | SCAC4 |
| 2537 | SDUE | SOUTHEAST ROAD BUILDERS INC | | | SCAC4 |
| 2538 | SDUF | S E L MADURO (FLA) INC | | | SCAC4 |
| 2539 | SDUG | SNEED TRUCKING | | | SCAC4 |
| 2540 | SDUK | SANDHU S TRUCKING | | | SCAC4 |
| 2541 | SDUP | STARDUST TRANSPORTATION LLC | | | SCAC4 |
| 2542 | SDUS | SOUTHLAND ANGUS | | | SCAC4 |
| 2543 | SDUT | STARDUST TRUCKING | | | SCAC4 |
| 2544 | SDV | Servicios Aereos Del Vaupes | | | ICAO1 |
| 2545 | SDVA | SANDOVAL CERVANTES, LUIS FERNANDO | | | SCAC4 |
| 2546 | SDVB | SUNSET DELIVERS INC | | | SCAC4 |
| 2547 | SDVD | STUMP TRANSPORTATION SERVICE | | | SCAC4 |
| 2548 | SDVE | STAR DELIVERY SOLUTIONS LLC | | | SCAC4 |
| 2549 | SDVF | SCOTT DISTRIBUTION SERVICE INC | | | SCAC4 |
| 2550 | SDVG | SANDOVAL TRUCKING | | | SCAC4 |
| 2551 | SDVI | SDV (USA) INC | | | SCAC4 |
| 2552 | SDVK | SANDOVALS TRUCKING | | | SCAC4 |
| 2553 | SDVN | SANDOVAL TRANSPORT | | | SCAC4 |
| 2554 | SDVP | STAR DELIVERY INC | | | SCAC4 |
| 2555 | SDVQ | SAMUEL DAVIDS SERVICES INC | | | SCAC4 |
| 2556 | SDVS | SAN DIEGO VAN & STORAGE CO | | | SCAC1 |
| 2557 | SDVS | SAN DIEGO VAN & STORAGE COMPANY | | | SCAC4 |
| 2558 | SDVY | STEWARTS DELIVERY | | | SCAC4 |
| 2559 | SDWB | STEWARD, W B & SON | | | SCAC4 |
| 2560 | SDWE | STUDIO WEST LTD | | | SCAC4 |
| 2561 | SDWF | SCHINDEWOLF EXPRESS INC | | | SCAC4 |
| 2562 | SDWG | SANCTIFIED TOWING LLC | | | SCAC4 |
| 2563 | SDWK | SADOWSKY | | | SCAC4 |
| 2564 | SDWL | SHADOW LINES | | | SCAC4 |
| 2565 | SDWM | SILVER DEW WORMS | | | SCAC4 |
| 2566 | SDWN | SIDHWAN TRANSPORTATION LTD | | | SCAC4 |
| 2567 | SDWP | SHADOW TRANSPORT INC | | | SCAC4 |
| 2568 | SDWQ | SOUTHERN DRAWL LLC | | | SCAC4 |
| 2569 | SDWT | SPEEDWELL TRANSPORTATION INC | | | SCAC4 |
| 2570 | SDWU | FRANS DE WIT INTERNATIONAL BV | | NL | BIC |
| 2571 | SDWU | FRANS DE WIT BV | | | SCAC4 |
| 2572 | SDWX | Cemex, Inc. | added 7/2005; 7/2005 | | NAKINA |
| 2573 | SDWX | *SOUTHDOWN, INC. | | | PWRC |
| 2574 | SDWX | +CEMEX, INC. | | | PWRC |
| 2575 | SDWX | CEMEX INC | | | SCAC4 |
| 2576 | SDWX | Cemex Inc. | | USA | TRAFFIC |
| 2577 | SDWY | SIDDOWAY SHEEP COMPANY INC | | | SCAC4 |
| 2578 | SDWZ | SOUTH DAKOTA WHEAT GROWERS | | | PWRC |
| 2579 | SDX | Servicio Tecnico Aero de Mexico, S.A. de C.V. | Callsign: Servicio Tecnico, | MEX | AVCODES |
| 2580 | SDX | Servicio Tecnico Aero De Mexico | | | ICAO1 |
| 2581 | SDX | Squire Dingee Co. | 7/1930-4/1961; eliminated 10/1963 | | NAKINA |
| 2582 | SDX | Squire Dingee Co. | 4/38-4/61 | | NRHS |
| 2583 | SDX | SQUIRE DINGEE CO. | | | PWRC |
| 2584 | SDXA | SEABIRD EXPLORATION | | | SCAC4 |
| 2585 | SDXC | SKY DISTRIBUTION EXPRESS INC | | | SCAC4 |
| 2586 | SDXD | SUMMERSID | | | SCAC4 |
| 2587 | SDXE | SAME DAY XPRESS LLC | | | SCAC4 |
| 2588 | SDXF | SUDDENLY EXPRESS CORP | | | SCAC4 |
| 2589 | SDXG | SANDY-X GROUP | | | SCAC4 |
| 2590 | SDXH | SUPERLOAD TRANSPORT LLC | | | SCAC4 |
| 2591 | SDXI | SHADDAI TRANSPORT INC, THE | | | SCAC4 |
| 2592 | SDXJ | SHEPHERD TRANSPORT INC | | | SCAC4 |
| 2593 | SDXK | SPEED DOX INC | | | SCAC4 |
| 2594 | SDXL | STRYD TRANSPORTATION LLC | | | SCAC4 |
| 2595 | SDXM | SNYDER TRANSPORTATION INC | | | SCAC4 |
| 2596 | SDXN | SEED-EX INC | | | SCAC4 |
| 2597 | SDXO | SALADA TRANSPORTATION | | | SCAC4 |
| 2598 | SDXP | SDX | | | SCAC4 |
| 2599 | SDXV | SIDLE TRANSIT SERVICE INC | | | SCAC4 |
| 2600 | SDY | Island Express | IATA: 2S, Callsign: Sandy Isle, IATA Prefix: 579, | USA | AVCODES |
