Originally Posted by
jhayes_1780
I *thought* there was some sort of "most significant carrier" (or something like that) on flights to/from EU.
As the itinerary touches the United States, the DOT rule preempts IATA convention and the marketing carrier of the first segment ("first marketing carrier" - UA) determines the allowance of the entire ticket. What's not clear is what class of service should apply.
MSC applies to journeys which do not touch the USA.