Originally Posted by
BingBongBoy
A friend works for Delta, and they fly on everything in the whole fleet, and are just about to have the 727 (from AirTran I believe) added to the fleet, so will end up flying on around 12 different types of aircraft... Unbelievable...

Do you mean 717?

I know US airlines do tend to fly much older birds than their European counterparts but I can't imagine anyone still flying the good old 727s! And I agree with you, I can imagine some joint certification (like 330 with 340, etc) but mixing, say, a 737, 320 and 717 would be rather absurd in my view.