I am looking at a potential trip that might lead me booking a United flight connecting to a Delta flight (separate tickets). And for once I might need to check a bag. So I am trying to find out if UA has an interline baggage agreement with Delta. And more generally, for ways to find out which interline agreements exist. Asking Alex was entertaining for a minute, but useless. Google wasn't helpful either. Is there an online resource that tracks this information? (I realize that several airlines have stopped interline baggage, but unless I missed it, United isn't among those... yet).