| 601 | LARX | Aetna Oil Co., a Division of Ashland Oil & Refining Co. | added 4/1954; 7/1954-4/1961; eliminated 1/1963 | | NAKINA |
| 602 | LARX | Aetna Oil Co., Inc. | 1/1941-1/1952; eliminated 4/1954 | | NAKINA |
| 603 | LARX | Aetna Oil Service, Inc. | 7/1930-4/1938 | | NAKINA |
| 604 | LARX | Aetna Refining Co. | 8/1920-7/1923 | | NAKINA |
| 605 | LARX | Aetna Oil Co., Inc. | 4/38-1/52; eliminated 4/54 | | NRHS |
| 606 | LARX | Aetna Oil Co., a Division of Ashland Oil & Refining Co. | added 4/54; 10/57-4/61 | | NRHS |
| 607 | LARX | Ashland Oil & Refining Co. | 7/65-10/66; eliminated 4/70 | | NRHS |
| 608 | LARX | *ASHLAND OIL & REFINING CO. [AETNA OIL CO.; AETNA REFINING CO.] | | | PWRC |
| 609 | LARX | *LEWISTOWN & AUBURN RAILROAD | | | PWRC |
| 610 | LARX | ASHLAND OIL & REFINING CO | | | SCAC3 |
| 611 | LARZ | *LANAN, INC. | | | PWRC |
| 612 | LARZ | *LITTLE AMERICA REFINERY | | | PWRC |
| 613 | LARZ | LANAN, INC | | | SCAC3 |
| 614 | LAS | Compania Aerea Lineas Ecuatoguineanas de Aviacion S.A. (LEASA) | Callsign: Leasa, | GQ | AVCODES |
| 615 | LAS | Ligne Aérienne Seychelles | IATA: JG, | SY | AVCODES |
| 616 | LAS | Skymedia AG | Callsign: Lions Helicopter, Name changed to Lions Air Skymedia AG d/b/a Skymedia. ICAO designator changed from RBL | CH | AVCODES |
| 617 | LAS | Lions Air Skymedia AG d/b/a Skymedia | Callsign: Lions Helicopter, Name changed from Skymedia AG. ICAO designator changed from RBL | CH | AVCODES |
| 618 | LAS | Louisiana Southern R.R. | added 4/2008 | | NAKINA |
| 619 | LAS | LOUISIANA SOUTHERN RAILROAD | | | PWRC |
| 620 | LAS | LOUISIANA SOUTHERN RAILROAD | | | SCAC4 |
| 621 | LASA | LINEAS AGROMAR S A | | | SCAC3 |
| 622 | LASB | Lackawaxen and Stourbridge R.R. Corp. | eliminated 1/1990 | | NAKINA |
| 623 | LASB | Lackawaxen and Stourbridge R.R. Corp. (transferred to New York, Susquehanna and Western Ry. Corp.) | added 10/1988 | | NAKINA |
| 624 | LASB | Lackawaxen and Stourbridge R.R. Corp. | added 7/1976; 1/1980; eliminated 10/1988 | | NAKINA |
| 625 | LASB | Lackawaxen and Stourbridge R.R. Corp. | added 7/76; 1/80; eliminated 10/88 | | NRHS |
| 626 | LASB | Lackawaxen and Stourbridge R.R. Corp. (transferred to New York, Susquehanna and Western Ry. Corp.) | added 10/88 | | NRHS |
| 627 | LASB | Lackawaxen and Stourbridge R.R. Corp. | eliminated 1/90 | | NRHS |
| 628 | LASB | LACKAWAXEN & STOURBRIDGE RAILROAD CORP. | | | PWRC |
| 629 | LASB | Lackawaxen and Stourbridge Railroad | | | RSRV |
| 630 | LASC | LASCARI, S V AND SONS INC | | | SCAC3 |
| 631 | LASCH | Lasch GmbH Zwickau | | DE | VKM |
| 632 | LASD | LASER EXPEDITE & LOGISTICS INC | | | SCAC4 |
| 633 | LASE | LANDERS SERVICE INC | | | SCAC3 |
| 634 | LASF | LASALLE FREIGHT COMPANY | | | SCAC3 |
| 635 | LASG | LASERSHIP | | | SCAC4 |
| 636 | LASH | LASHAM LEASING COMPANY, INC. | | | SCAC3 |
| 637 | LASH | LOS ANGELES SUPERIOR TRANSPORTATION | | | SCAC4 |
| 638 | LASI | LASALLE TRUCKING INC | | | SCAC3 |
| 639 | LASJ | L A S LEASING INC | | | SCAC4 |
| 640 | LASM | LOS ANGELES-SEATTLE MTR | | | PWRC |
| 641 | LASN | LASATER, WILLIAM MOTOR LINES | | | SCAC3 |
| 642 | LASO | LENGNER & SONS PRODUCE EXPRESS | | | SCAC3 |
| 643 | LASPEZ | ATC La Spezia | City: La Spezia | I | TRAFFIC |
| 644 | LASQ | LA SALLE CARTAGE COMPANY INC | | | SCAC3 |
| 645 | LASR | LASHAM-REVERE MOTOR SERVICE, INC | | | SCAC3 |
| 646 | LASS | LAWSON BROS | | | SCAC3 |
| 647 | LAST | LA SALLE TRUCKING COMPANY | | | SCAC3 |
| 648 | LASU | SOCOMAT SAS | | F | BIC |
| 649 | LASU | SOCOMAT | | | SCAC4 |
| 650 | LASV | LAS VEGAS TRUCK LINE, INC | | | SCAC3 |
| 651 | LASW | LASHWAY, LEO E TRUCKING CO | | | SCAC3 |
| 652 | LASW | LAND AIR & SEA WORLDWIDE | | | SCAC4 |
| 653 | LASX | Lutz & Schramm, Inc. | 4/1938-10/1957; eliminated 4/1960 | | NAKINA |
| 654 | LASX | Lutz & Schramm Co. | 7/1923-7/1937 | | NAKINA |
| 655 | LASX | Lutz & Schramm, Inc. | 4/38-10/57 | | NRHS |
| 656 | LASX | LUTZ 7 schramm co. | | | PWRC |
| 657 | LASY | LASLEY TRUCKING COMPANY INC | | | SCAC3 |
| 658 | LAT | Lebanese Air Transport (Charter) Co. S.A.L. | Callsign: Lebanese Air, | RL | AVCODES |
| 659 | LAT | Lebanese Air Transport (Charter) | | | ICAO1 |
| 660 | LAT | LAT Fernmelde, Montage und Tiefbau GmbH | | DE | VKM |
| 661 | LATA | LATONA TRUCKING INC | | | SCAC4 |
| 662 | LATC | LARSON TRANSPORTATION COMPANY | | | SCAC3 |
| 663 | LATD | LA TRANSPORT | | | SCAC4 |
| 664 | LATG | L A TRANSPORT LTD | | | SCAC3 |
| 665 | LATH | LATHAM, HAROLD A | | | SCAC3 |
| 666 | LATI | L & A TRUCKING CO | | | SCAC3 |
| 667 | LATJ | LAMONTAGNE, ALLEN T | | | SCAC4 |
| 668 | LATM | LATHAM TRUCKING COMPANY | | | SCAC3 |
| 669 | LATO | L & S SPECIAL EXPRESS CO | | | SCAC3 |
| 670 | LATO | L & S | | | SCAC4 |
| 671 | LATP | LATHROP, CLIFFORD R INC | | | SCAC3 |
| 672 | LATP | L A TRANSPORTATION INC | | | SCAC4 |
| 673 | LATQ | LANG TRANSIT INC | | | SCAC3 |
| 674 | LATQ | L A TRANSPORT LTD | | | SCAC4 |
| 675 | LATR | LACOSTE TRUCKING | | | SCAC3 |
| 676 | LATR | L AND A TRUCKING LLC | | | SCAC4 |
| 677 | LATS | LANGE TRANSFER & STORAGE COMPANY | | | SCAC3 |
| 678 | LATS | LOGISTICSA TODAY LLC | | | SCAC4 |
| 679 | LATT | L A TUCKER TRUCK LINES INC | | | PWRC |
| 680 | LATT | L A TRUCKING | | | SCAC3 |
| 681 | LATT | L A TRUCKING | | | SCAC4 |
| 682 | LATU | FLEX BOX SA DE CV | | MEX | BIC |
| 683 | LATU | Transatlantic Lines | | | RSRV |
| 684 | LATU | LUNITRANS N.V. | | | SCAC3 |
| 685 | LATU | TRANSATLANTIC LINES LLC | | | SCAC4 |
| 686 | LATV | LATOURS MOVING & STORAGE | | | SCAC3 |
| 687 | LATV | LATVIAN AMERICAN SHIPPING LINE | | | SCAC4 |
| 688 | LATW | LASTA TRANS INC | | | SCAC4 |
| 689 | LAU | Lineas Aereas Suramericanas SA t/a LAS, S.A. | IATA: 4L, Callsign: Suramericano, IATA Prefix: 174, | CO | AVCODES |
| 690 | LAU | Líneas Aéreas Suramericanas | | | ICAO1 |
| 691 | LAU | Connex Sachsen GmbH (Lausitzbahn) | This company used to be known as Lausitzbahn, but because they also started operating trains outside the Lausitz region the name was changed to Connex Sachsen. They operate passenger trains on Cottbus-Görlitz-Zittau, Leipzig-Bad Lausick-Geithain and a few trains on Görlitz-Bischofswerda-Dresden. Early in 2006 Connex was renamed in Veolia Verkehr. | D | TRAFFIC |
| 692 | LAUA | LAUBACHER, MIKE TRANSPORTATION CO | | | SCAC3 |
| 693 | LAUA | LAUBACH EXPEDITED SERVICE LLC | | | SCAC4 |
| 694 | LAUBAG | Lausitzer Braunkohle AG | | D | TRAFFIC |
| 695 | LAUC | LAU, C E | | | SCAC3 |
| 696 | LAUC | L A TRUCKING | | | SCAC4 |
| 697 | LAUD | LAVIGNE, ROBERT AUDIO | | | SCAC4 |
| 698 | LAUDE | Laude Smart Intermodal S.A. | Real: LAU | PL | TRAFFIC |
| 699 | LAUF | LAUFENBERG TRANSPORTATION INC | | | SCAC3 |
| 700 | LAUF | LAUFENBERG TRANSPORTATION INC | | | SCAC4 |
