Originally Posted by
lincolnjkc
I think the same logic that applies with interline checked bags and interline misconnects fits in nicely here:
Except that IATA member airlines have explicit agreements in place for mishandled interline checked bags and for misconnects, but AFAIK don't have such agreements in place for dealing with EC261 and similar compensation. And EC261 itself is surprisingly vague about how connections work, let alone interline connections, codeshares, etc.
Absent an IATA or other agreement between DL and UA on who is responsible, it's between the pax and each airline (via the courts, ultimately) as to whether they're owed EC261 comp.
I still think pax had a ticket on United; United failed to deliver them on time; United owes the comp.
I still think Delta will pay if you file with them, but only because their systems for processing EC261 compensation claims aren't that sophisticated.