A list of aircraft operators that have that have suffered an accident, serious incident or hijacking. The list may also contain defunct airlines or airlines that in the meantime have changed their name or have merged.

Airlines:
Dancing Wind Aviation
DB Aviation
DDH Aviation
Deer Horn Aviation
Delaware Air Freight
Delta Air Lines
Delta Connection
Delta Private Jets
Denver Air Connection (part of key Lime Air)
DePonti Aviation Company
Desert Air Transport
Dexter Air
DHL Airways (renamed ASTAR Air Cargo May 2003)
DMC Flying Service
Dodita Air Cargo
Dolphin Airways
Dolphin Aviation
Dolphin Express Airlines
Downeast Airlines (founded as Mid-Coast Airways, renamed 1968)
DP Air
Duncan Aviation
Dynamic International Airways

Corporations:
Dallas Chapter
Danpar Aviation
DC Aviation, LLC
DEKA Research & Development Corp.
Delta Star Inc.
Delwood Furniture
Desert Sand Aircraft Leasing
Dewberry Air LLC
Diamond Jet Inc.
Digicut Systems
Digital Equipment Corporation
Dinama Aircorp
Dirt Dynamics, Inc.
Donna Blue Aircraft Inc.
Dow Chemical Company
DR & M Incorporated
Drayton Associates
Drilling Muds
Drug Plastics & Glass Company Inc
DRW Financial
DRWS Services LLC
Du Pont de Numours and Co.
Dufresne Inc.
Dumas Milner Corp.
Duncan Aircraft Sales
Durakool Inc
Dwiggins LLC
Dynamic Aviation Group Inc
Dynamic Avlease

Manufacturers:
Douglas Aircraft Company (Merged with McDonnell Aircraft Corporation into McDonnell Douglas)

Private:
D. Cavener
D. Seitz
Darryl G. Greenamyer
David K. Gifford
Dolph Briscoe Jr.
Donald L. Baker
Douglas M. Lacey

Unknown:
DK&L Company
Dragon Air Leasing Inc.