Why do people on airplanes often have tomato juice as a drink?

Because it's good?

There is no glibness here, just innocence. I like tomato juice, at least compared to other juices, tasty, not too sweet, not too bitter, but I'm generally not a juice fan.

I'd much rather drink coffee, water, beer, or wine. Now beer and wine will cost me on a plane (mostly), and I may want to avoid the depressant effects (air travel being harsh enough on the system), especially if I am driving soon after, or if I've gone more than a few hours east.

That leaves water or coffee. I've learned to manage my caffeine levels pretty well, so beyond a certain point/time, coffee is verbotten (unless they have decaf, ha ha ha); cf comments on alcohol consumption above, stimulants are avoided for similar reasons.

That leaves water.

The first few glasses are fine. The next few are boring beyond belief.

As for other juices, well, orange burns my stomach and irritates my lips, I might have one glass every year or two. Apple is insipid; maybe a glass or two a year. Other fruit juices are generally too sweet.

Soft drinks are too sweet. Period. Not a fan, haven't been since all night D&D sessions in high school.

That leaves tomato juice and sparkling water.

EDIT: Do people really order more tomato juice, or are you under the effect of the availability heuristic?

I always order it, just because I like tomato juice. I didn't realize it was that common to order it on airplanes...

That having been said, it does a really good job of coating and soothing your throat if it's dry/scratchy/starting-to-get-sore. Given how often that happens while flying, I'd wager that plays a role in tomato juice's popularity on planes.

I tried this the last time I traveled. The stewardess gave me a big smile when I ordered it, but when I got the drink, I didn't notice any taste difference. I also regretted ordering it since I'm not a fan of tomato juice in general.