Ryanair 737s
At Manchester today, I saw one labelled "Bye bye Latehansa." He takes the biscuit for cheek, Michael O'Leary. I also recall "Arriverderci Alitalia" a few years ago.
It probably sounds sniffy, but personally I think putting this kind of brash slogan on an airliner cheapens it-just like those silly "Keep Duty free" decals on Britannia's aircraft in the late 1990s.