Strange that they are not very up-front in saying that this flight is operated by another carrier. They have the usual asterisk saying that some flights may be operated by partners, which they usually use for United Express segments, but Aer Lingus is on the list.

I suppose that when one does an actual search, the results state that the flight offered is operated by Aer Lingus, but, still, I would expect a bit more clarity in the marketing.