Thanks to commenter Rich, my question yesterday has been answered. The airliner with the squished Santa on its nosecone turns out to have been a Boeing 737-800 of Ryanair.
Still no word on when or where the aircraft was painted, but full marks to Ryanair for their sense of humor! It seems they've painted a number of their aircraft in odd ways from time to time. You'll find a number of photographs of them here (scroll down to find the pictures).
Thanks, Rich. Appreciate your help.