Hans - you may already know this -
a small piece of Americana
back in the 1930's - early 1950s - all the places where a guest payed to stay overnight were called hotels (except lodges - like in Yosemite). In the 1950's (I don't remember who's idea it was - probably find it on google) a new concept came along. It was a "hotel" that you could could drive your motor vehicle right to the door of your room.
So a motor-hotel, became a motel. That is the difference between the 2.