Sorry for the awkward title. Didn't know how to word it better.
In the 70s, my parents flew from ORY to PEK on Ethiopian. I believe they stopped in Rome, Addis, and maybe Delhi. At the time, Ethiopian was one of the few if not the only way to fly from France to PEK
Anyway, that was one flight, on one airplane, with one number.
It was not too unusual, at that time, to fly THROUGH the homebase of an airline without changing plane, and still go on very far (I'm not talking about a little domestic hop at the beginning or at the end).
I don't believe that is done anymore by any carrier. Whether you stop in Frankfurt, Addis, Chicago or Karachi, you get off the plane, and into another one with a different flight number, right?