American and Delta failed to renew their agreement on interlining, a longtime practice enabling a single ticket for flights on multiple, unaligned airlines and associated baggage transfers. It also allows a carrier to reaccommodate a competitor's disrupted passengers. Corporate travel repercussions from the AA-Delta interline gap will be limited, but in some cases may cause inconvenience and added cost.
When travelers book a negotiated rate (or any other private fare), it's probably not an interlined ticket in the first . . .