Regulation text:
Scope
1. This Regulation shall apply:
(a) to passengers departing from an airport located in the territory of a Member State to which the Treaty applies;
(b) to passengers departing from an airport located in a third country to an airport situated in the territory of a Member State to which the Treaty applies, unless they received benefits or compensation and were given assistance in that third country, if the operating air carrier of the flight concerned is a Community carrier.
So to UA or DL operated flights, the regulation does not apply. If a third country has rules in place for flights departing their country, said rules override the regulation for community carriers as well.