Mr. & Mrs. T Bloody Mary Mix
I don't know why ginger ale is such a popular drink of choice on airplanes, but I suppose it's partially because it's not often that one finds it (at least, compared to Coke at places like McDonald's and such). In a similar line of thought, canned Bloody Mary Mix (sometimes called simply "spicy tomato juice") is something that I'll usually try to get whenever I fly American airlines, but is not necessarily anything that I'll regularly try to seek out outside of an airplane. Sure, this canned stuff has a bit of an artificial taste to it and could be much fresher, but it still packs a burst of savory and spicy flavors (in fact, perhaps a bit too much since I usually take it virgin without any vodka to loosen it up).
On a side note, it looks like United has swapped out its usual porcelain bar nut cups for cheapie little disposable foil ones. It doesn't really make a difference to me, but it is interesting to note.