Instead or aeroplane.
real-ator instead of realtor.
Being a Brit in Canada, I see a few in the Canadian pronunciations but a heap from the US, as you say though, they are usually just spelling differences.
A niggler of mine (I said niggLER) is when you say 'Thank you, goodbye" or "Thanks for your help" to an American (usually on the phone) and they reply, "Uh-huh" or more eloquently "m-kay, uh-huh".
It just seems so aloof and incredibly rude.