Not a lot. Since more knowledgeable sources have corrected me re the sharklets on the outside, I'm guessing the only real aesthetic difference is going to be a larger engine on the NEO (correct me if I'm wrong), and the difference with the economy seats from about row 13 back - the newer slimline seats are notably different to look at - they don't recline, have notably smaller trays and I don't think the headrest is as adjustable (if at all?).


Not a BA plane, but demonstrates the engine differences between NEO (left of image) and CEO (right of image) aircraft.