Not interchangeable; all nonstop flights are direct (how could they not be?) but not all direct flights are nonstop, although I understand that in the official industry jargon they do not overlap.It does kinda read that way...
What I meant was that in many years I haven't been on a flight that stopped someplace and then took off again without my having to exit the aircraft. The last I can remember was something like 30 years ago when I was on a HOU - CZM flight that stopped in CUN first.What have you been on that would require a new definition?
Aside: Before that I was on a commuter airline flight between Austin and Birmingham that had scheduled stops in Taylor, TX, and Little Rock, AR. Soon after we left Austin, the copilot turned to us and said, "We don't have any scheduled pickups or dropoffs in Taylor; does anyone mind if we skip that stop?" No one did, so we flew on to Little Rock.