| 5101 | RKCX | Knox Kershaw Co., Inc. | added 1/69; 4/70-1/80; eliminated 4/85; 1/94-7/2000 | | NRHS |
| 5102 | RKCX | *KNOX KERSHAW INC (ROYCE KERSHAW CO., INC.) | | | PWRC |
| 5103 | RKCX | Knox Kershaw | | | RSRV |
| 5104 | RKCX | KNOX KERSHAW INC | | | SCAC4 |
| 5105 | RKCY | RANDOLPH PACKING CO | | | SCAC4 |
| 5106 | RKDA | ROCKDALE TRANSPORTATION ENTERPRISES | | | SCAC4 |
| 5107 | RKDB | ROCK LEASING INC | | | SCAC4 |
| 5108 | RKDC | ROCKSIDE DISTRIBUTION CENTER | | | SCAC3 |
| 5109 | RKDC | ROADSTAR TRUCKING INC | | | SCAC4 |
| 5110 | RKDF | R K D FARMS | | | SCAC3 |
| 5111 | RKDF | RINKER BOAT COMPANY LLC | | | SCAC4 |
| 5112 | RKDG | R K D TRUCKING INC | | | SCAC3 |
| 5113 | RKDG | ROGERS TRUCKS & EQUIPMENT INC | | | SCAC4 |
| 5114 | RKDI | ROCKETT DELIVERY SERVICE | | | SCAC3 |
| 5115 | RKDL | RINKER, DALE F | | | SCAC3 |
| 5116 | RKEB | RIDDICK ENTERPRISES INC | | | SCAC4 |
| 5117 | RKED | ROAD KING ENTERPRISES AND DISTRIBUT | | | SCAC4 |
| 5118 | RKEE | R & K EXPRESS INC | | | SCAC4 |
| 5119 | RKEF | ROAD KING EXPRESS FREIGHT INC | | | SCAC4 |
| 5120 | RKEI | ROCKET EXPRESS INC | | | SCAC3 |
| 5121 | RKEN | ROCKET TRANSPORTATION INC | | | SCAC3 |
| 5122 | RKEN | RYKER ENTERPRISES INC | | | SCAC4 |
| 5123 | RKEP | ROCKET EXPRESS | | | SCAC3 |
| 5124 | RKEQ | ROCKEY, M F MOVING COMPANY | | | SCAC3 |
| 5125 | RKEQ | ROCKY BAR RANCH | | | SCAC4 |
| 5126 | RKER | R K DISTRIBUTING INC | | | SCAC4 |
| 5127 | RKES | ROCKET EXPRESS INC | | | SCAC3 |
| 5128 | RKES | ROCKIN K ENTERPRISES LLC | | | SCAC4 |
| 5129 | RKET | ROCKET TRUCKING | | | SCAC3 |
| 5130 | RKEV | RACE KIT EVENT SERVICE INC | | | SCAC4 |
| 5131 | RKEY | ROCKFORD, KERRY ENTERPRISES INC | | | SCAC4 |
| 5132 | RKFC | ROCKFORD CARRIER INC | | | SCAC4 |
| 5133 | RKFI | R K FUELS INC | | | SCAC4 |
| 5134 | RKFL | ROCK FALLS FREIGHT & LEASING CORP | | | SCAC3 |
| 5135 | RKFM | REMARK FRESH MARKETS | | | SCAC4 |
| 5136 | RKFT | RKF TRUCK LINES LTD | | | SCAC3 |
| 5137 | RKG | Rockingham R.R. (Co.) | 7/1923-10/1966 | | NAKINA |
| 5138 | RKG | Rockingham R.R. Co. | 4/38-10/66 | | NRHS |
| 5139 | RKG | ROCKINGHAM RAILROAD CO. | | | PWRC |
| 5140 | RKGI | R & K LOGISTICS INC | | | SCAC4 |
| 5141 | RKGL | RICE TRUCKING LLC | | | SCAC4 |
| 5142 | RKGN | RESOURCES TRUCKING OF CALIFORNIA IN | | | SCAC3 |
| 5143 | RKGP | ROCKING R TRANSPORT | | | SCAC4 |
| 5144 | RKGQ | RKG CARRIERS INC | | | SCAC4 |
| 5145 | RKGT | ROCKING T INC | | | SCAC4 |
| 5146 | RKGX | River King Coal | | | RSRV |
| 5147 | RKH | Royal Khymer Airlines | IATA: FE, Callsign: Khymer Air, Designator FE recalled by IATA | K | AVCODES |
| 5148 | RKH | Royal Khmer Airlines | IATA: RK, Callsign: Khmer Air, Designator RK reinstated by IATA. Designator FE recalled by IATA | K | AVCODES |
| 5149 | RKH | Royal Khmer Airlines | IATA: RK | | ICAO1 |
| 5150 | RKH | Regionalverkehr Kurhessen GmbH | | D | TRAFFIC |
| 5151 | RKHA | ROCK HAULERS INC | | | SCAC3 |
| 5152 | RKHA | ROCKET DELIVERY INC | | | SCAC4 |
| 5153 | RKHD | RKH INDUSTRIES INC | | | SCAC4 |
| 5154 | RKHI | RICH TRUCKING INC | | | SCAC4 |
| 5155 | RKHJ | ROCKHILL, H J INC | | | SCAC3 |
| 5156 | RKHU | RIN KAGAKU KOGYO CO LTD | | J | BIC |
| 5157 | RKIA | ROCK-IT CARGO USA LLC | | | SCAC4 |
| 5158 | RKIB | ROCK-IT CARGO USA LLC | | | SCAC4 |
| 5159 | RKIC | ROCK-IT CARGO USA INC | | | SCAC3 |
| 5160 | RKIC | ROCK-IT CARGO USA LLC | | | SCAC4 |
| 5161 | RKIG | ROYAL KING ENTERPRISE LTD | | | SCAC4 |
| 5162 | RKIK | RKI | | | SCAC4 |
| 5163 | RKIP | ROCK IMPLEMENT INC | | | SCAC3 |
| 5164 | RKIT | RANKIN TRUCKING, INC | | | SCAC3 |
| 5165 | RKIW | ROCK-IT CARGO USA LLC | | | SCAC4 |
| 5166 | RKK | Stephens Investment Holdings, LLC | Callsign: Rocktown, | USA | AVCODES |
| 5167 | RKKG | ROOKS TRUCKING CO | | | SCAC4 |
| 5168 | RKKL | RKT TRUCKING LLC | | | SCAC4 |
| 5169 | RKL | Air Caledonie International | IATA: SB, Callsign: Aircalin, ICAO designator changed to ACI. Founded in 1983 | NC | AVCODES |
| 5170 | RKLC | RK LOGISTICS GROUP INC, THE | | | SCAC4 |
| 5171 | RKLD | REEDEREI NORD KLAUS E OLDENDORFF LT | | | SCAC3 |
| 5172 | RKLE | RICKARD, LEE | | | SCAC3 |
| 5173 | RKLG | RK LOGISTICS GROUP INC, THE | | | SCAC4 |
| 5174 | RKLI | RKL ENTERPRISES INC | | | SCAC4 |
| 5175 | RKLL | ROAD KING LOGISTICS LLC | | | SCAC4 |
| 5176 | RKLU | RENTOKIL LTD | | | SCAC3 |
| 5177 | RKM | RAK Airways | IATA: RT, Callsign: Rakair, Founded in 2006. Suspended operations 01 January 2014. Desigantor RT recalled by IATA | UAE | AVCODES |
| 5178 | RKM | RAK Airways | | | ICAO1 |
| 5179 | RKMC | ROKUCHU MARINE CORPORATION | | | SCAC3 |
| 5180 | RKMC | ROCKY MOUNTAIN CARGO LLC | | | SCAC4 |
| 5181 | RKMD | ROCKY MOUNTAIN DELIVERY & TRANSPORT | | | SCAC3 |
| 5182 | RKMI | ROCKET MESSENGER SERVICE INC | | | SCAC3 |
| 5183 | RKMI | RK MACHINE INC | | | SCAC4 |
| 5184 | RKMK | RICKMAN TRUCKING CO INC | | | SCAC4 |
| 5185 | RKML | ROCKY MOUNTAIN LIVESTOCK TRUCKING I | | | SCAC3 |
| 5186 | RKMM | ROCKY MOUNTAIN MOVING & STORAGE INC | | | SCAC3 |
| 5187 | RKMN | RKM EQUIPMENT & TRUCKING INC | | | SCAC3 |
| 5188 | RKMO | ROCKY MOUNTAIN FREIGHT CONSOLIDATOR | | | SCAC3 |
| 5189 | RKMP | RKM TRANSPORT | | | SCAC3 |
| 5190 | RKMP | ROCK BOTTOM EXPRESS | | | SCAC4 |
| 5191 | RKMR | ROCKY MOUNTAIN RENTAL | | | SCAC3 |
| 5192 | RKMR | REKORD MARINE ENT LTD | | | SCAC4 |
| 5193 | RKMS | ROCKY MOUNTAIN SHIPPERS | | | SCAC3 |
| 5194 | RKMU | TARASCONI TRASPORTI SRL | | | SCAC4 |
| 5195 | RKMV | ROCKEYS MOVING & STORAGE LLC | | | SCAC4 |
| 5196 | RKMW | Chicago, Rock Island and Pacific R.R. Co. | 1/1980 | | NAKINA |
| 5197 | RKMW | Chicago, Rock Island and Pacific R.R. Co. | Jan-80 | | NRHS |
| 5198 | RKMW | CHICAGO, ROCK ISLAND & PACIFIC RAILROAD (ROCK ISLAND), MILWAUKEE ROAD OPERATIONS | | | PWRC |
| 5199 | RKMW | Chicago, Rock Island and Pacific Railroad | | | RSRV |
| 5200 | RKN | Shakh Air KZ | Callsign: Kanion, | KZ | AVCODES |
