Dalian Airlines, Dalian, V.R.China, founded 2011(subsidary of Air China).    -   #1:

DAN-AIR, UK, 1953-1992. Integrated 1992 into BA.
  -   #2,                                             #3(12cmW)/#7(15cmW),                                    #1:

       -                        #10,                                                                   #4:

DANA AIR, Ikeja/Lagos, Nigeria, founded 2008.
IATA:9J,  ICAO: DAN,  Callsign:  DANACO.   #1

Danish Airforce, Royal; Copenhagen.   #1:

DAT . Danish Air Transport, Esbjerg, Denmark, founded 1989.   -  #1(normalpaper)/#2(glossy):

DELTA, Atlanta, Georgia, USA, founded 1934.
- Paper bags:    #10,                  #1/#11(small text variation),                      #18:

-  Paper bags:         #6,                                #2,                                    #3:

-  Paper bags:           #4(front and rear),                                              #8:

- Paper bags:    #5,                          #7,                            - Plastic bag       #20:

Plastic bags front n rear: #9,  #22/#29/#31w/o or small LK/#25/#26(big LK) n more variations:

- Plastic bags #36(front and rear)/#37(addtnl at base small+)/#34(Reg 3mm dia) 
                                                            /Paper bags #38(plain flat base),  #29(sealed base):                                      
 
Deutsche BA, Munich, Germany, 1992-2008.
   -           #1(normal paper)/#4(glossy),             #2,                                           #3:
        
DINAR, Salta, Argentina, 1992-2002.   -   #1:

Discover Airlines, Frankfurt, Germany, founded 2023 by renaming from Eurowings Discover(q.v.). -  #1:

Dniproavia, Dnipropetrovsk, Ukraine, founded 1996.    -  #2:

Donghai Airlines, Shenzhen, China, founded 2002.    -    #2(front and rear shown):

Dragonair, Hongkong, 1986-2016 renamed to Cathay Dragon(q.v.).
-              #13,                                                                     #11:

-      #4,                                             #17/#20 front,                            #20 rear:

-              #12,                                                                      #1:

Drukair, Paro, Bhutan, founded 1981.  -#1   and    #2(2010-8 JUL)/#2a(APR 2012-25):

-   #3:

Dubai Air Wing, U.A.E., Government Airline of Dubai, date of foundation uncertain. -  #1,   # 2,    #3:

Dubrovnik Airline, Dubrovnik, Croatia, 2004-2011.       -    #1:

Dutch Bird, Amsterdam, Netherlands, 2000- 2004.      -    #1:

DDA Dutch Dakota Association, Amsterdam, Netherlands, founded 1982.
Operating historic Douglas Aircrafts.       -  #1: