Not sure I understand your reasoning. I'm aware of "Fair Use" as a doctrine applying to copyrights but don't see how that applies when citing a vendor's product in a menu. In the menu, United is citing another vendor's product so I think are required to note when they are using said vendor's trademarked phrases or labels if the vendor requests it. Perhaps there's an IP attorney on this board who could clarify?
Regardless, this is a really petty matter to be griping about.