"Roland Perry" wrote in message

In message , at 11:36:29 on Sun,
11 Sep 2011, Clive D. W. Feather remarked:
BA certainly used to have "set-down only" stops. So the flight from
London to Pittsburgh (IIRC) had a set-down stop at Washington Dulles.
Those passengers to Pittsburgh just stayed on the plane while those
to Washington got off, after which the plane continued on its
journey.

20 years ago I recall catching a plane that flew
Gatwick-Houston-Dallas, probably a route BA inherited from BCal. We
didn't have to get off at Houston, but I suspect no-one got on either
(trade barriers) so we could be treated as 100% international
arrivals in Dallas.

Exactly -- if the onward flight can pick up pax, then everyone on the
arriving flight has to get off and go through security before proceeding
further. As BA flights aren't allowed to pick up internal US pax, they
have to be set-down only at the first US port. I think Qantas has a
similar arrangement with the LAX-JFK extension of its flight from
Sydney.

Years ago, I used to have fly regularly to Detroit, and the BA flights
used to go via Montreal for a while. BA were allowed to pick up pax for
the Montreal-Detroit leg, though there seemed to be few takers. As that
was an international leg, the pax from London stayed on-board during the
Montreal stop, and didn't have to deal with Canadian customs and
immigration.