Wed Sep 14, 2016 12:56 am
By 3-class I'm guessing you are alluding to a separate F, J, and Y concept (not F/J, Y+, Y). Here's a couple dedicated 3-cabin narrow body examples:
Present:
AA A321T has 3 separate classes of service
Past:
UA B752 "P.S." had 3 separate classes of service
Hope this at least helps a bit,
KLM11
BENAIRE - The Refined Airline