aerospaceair

Estonian Air

Flown them.

My possibly unique airline:
*Sun Vest Airlines
 

Broke this post down into aircraft that are non Delta and those that are (with those that are also in both categories):

(private)
C172, C182, S35, PA28

(non DL)
C402 (9K)
S340 (SunVest, AA)

A340 (LH)

748 (KE)

77W (JL, NH)

MD83 (AA)
 

DL overlapping others:
L1011

722 (also MX)

712 (also HA, QF)

732

733 (also US)

737

738 (also AA, QF, VA)

739 (also KE)

744 (also NW, QF)

DC9 (forget variants, also NW)

752 (also AA, AY, US)

753

762,

763 / ER (also AA)

764ER

772 (also AA, NH)

77L

A319 (also AA, NK, UA)

A320 (Also AA, F9, LH, VY)

A321 (also AA)

A333
MD88
MD90

(DL+other regionals below)

CR2

CR7

CR9

E145 (also AA)

E175 (also AA)

A72

I remember Airline Empires being big back in middle school in the mid 2000s. Haven't played a round in a long while but I do remember at the time being in the Ace Alliance (when they existed) under Timsher's leadership constantly duking it out with the WAA (which I later joined). I do see another WAA member in this thread though which makes me happy.