| 1 | CLK | Clark Aviation Corp. | Callsign: Clarkair, | USA | AVCODES |
| 2 | CLK | Clark Aviation | | | ICAO1 |
| 3 | CLK | Cadillac & Lake City Ry. Co. | 7/1965-10/1966 & 1/1975; eliminated 7/1976; added 7/1978; added 10/1978; 1/1980; eliminated 4/1990; 1/1994 | | NAKINA |
| 4 | CLK | Cadillac & Lake City Ry. Co. | 7/65-10/66 & 1/75; eliminated 7/76; added 7/78; added 10/78; 1/80; eliminated 4/90; 1/94 | | NRHS |
| 5 | CLK | RETIRED 05-26-94 ATP (093) [CADILLAC & LAKE CITY RY.] | | | PWRC |
| 6 | CLK | Cadillac and Lake City Railway | | | RSRV |
| 7 | CLKA | CLARK, WILLIAM B | | | SCAC3 |
| 8 | CLKA | CLARKS TRANS | | | SCAC4 |
| 9 | CLKB | CLARK, WILLIAM S | | | SCAC3 |
| 10 | CLKC | CLARK, ZEPHIA ODELL | | | SCAC3 |
| 11 | CLKD | CLEARLINK SHIPPING | | | SCAC3 |
| 12 | CLKF | CLARK FARMS | | | SCAC3 |
| 13 | CLKG | CLARKS TRUCKING & EXCAVATING INC | | | SCAC3 |
| 14 | CLKG | C & L TRUCKING | | | SCAC4 |
| 15 | CLKH | CLARK, W V HARVESTING | | | SCAC4 |
| 16 | CLKI | CHALKER TRANSFER | | | SCAC3 |
| 17 | CLKJ | C & L TRUCKING LLC | | | SCAC4 |
| 18 | CLKK | CLARKE TRUCKING | | | SCAC3 |
| 19 | CLKK | CLARK TRUCKING | | | SCAC4 |
| 20 | CLKL | CLARK TRUCK LINE | | | SCAC3 |
| 21 | CLKM | CLARK, TERRY | | | SCAC3 |
| 22 | CLKN | CLARK, CLARENCE | | | SCAC3 |
| 23 | CLKO | CLARK TRANSFER CO | | | SCAC3 |
| 24 | CLKP | CLARK TRANSPORTATION INC | | | SCAC3 |
| 25 | CLKQ | CLARK, BILL DELIVERY SERVICE | | | SCAC3 |
| 26 | CLKR | CLARKS TRANSFERRING SERVICE, INC | | | SCAC3 |
| 27 | CLKR | C L D TRUCKING INC | | | SCAC4 |
| 28 | CLKS | CLARK TRUCK LINE | | | SCAC3 |
| 29 | CLKS | CLARK SERVICES | | | SCAC4 |
| 30 | CLKT | CLARK TRANSFER, INC | | | SCAC3 |
| 31 | CLKT | CLARK TRANSFER INC | | | SCAC4 |
| 32 | CLKU | CALT(CITY AIRPORT, LOGIS&TRAVEL) | | ROK | BIC |
| 33 | CLKU | CONTAINERLINK LIMITED | | | SCAC3 |
| 34 | CLKV | CLARK, JOHN D | | | SCAC3 |
| 35 | CLKW | CLARK, HOWARD W INC | | | SCAC3 |
| 36 | CLKW | CLARK LAKE TRUCKING INC | | | SCAC4 |
| 37 | CLKY | CLUKEY, F W TRUCKING INC | | | SCAC3 |
