Originally Posted by
MWRFlyer
You can use the expert settings on .bomb to see classes of service offered when you are looking a prospective flights or when you make a dummy booking.
That by itself doesn't help. Lots of 2-cabin aircraft show C D Z buckets. 3-cabin flights tend to be between hubs and utilize 777s and 767-300s (and the odd 747). Short of checking the seatmap for flights with these types of aircraft there really is no way to know.