The answer’s more complicated than I thought. Oliver Smith explains.
Perhaps the biggest issue … is scientific. At high altitudes our taste buds simply don’t work properly. The low humidity dries out our nasal passages, and the air pressure desensitises our taste buds, which is why airline often opt for salty stews or spicy curries. Airlines planning a new menu will often taste food and wine on board a flight before clearing it for public consumption, because of the variation in taste. Some airlines install sealed rooms in their kitchens room to replicate the experience of eating in the sky.
The other major problem is logistics and costs. One of the best explanations of these various barriers was given by Jay Wacker, a professor of physics at Stanford University. Responding to the question “Why is airplane food so terrible?” on the website Quora, he issued this eloquent and thorough response:
“Because it is really hard, though not impossible.
. . .
For a hot meal right after take off, you have to make a meal that can take being heated for a long period of time in the serving container. The food is precooked or par-cooked and kept at temperature (they can’t do on-the-spot cooking, and they don’t have the energy budget to cook-then-refrigerate-then-reheat). The shortest hold times are usually about 60 to 90 minutes. So except for stews, say goodbye to any delicate proteins. Vegetables are even tough to do well. A lot of starches begin to break down. Nevertheless, if you notice, you get the best meal right after take-off (and why they serve dinner at 4pm) because it is easiest high quality meal to get to the passengers.
For meals served well after take-off (usually trans-oceanic flights only), they have to heat from scratch. The ovens are pretty terrible, totally packed with food (450 meals from a few galleys), not consistent heating, and operating on a tight energy budget. You can’t afford to undercook anything or burn something, so you have to be super-careful about choices.
Once you take into account the immense variety of dietary restrictions that airplanes have to cater to: vegetarians, vegans, pescatarians, allergies of all different varieties, spice-haters, lactose intolerance, pregnant women, people with suppressed immune systems, etc and you start to realize just what type of situation these airlines are in: being something for everyone. Ultimately, you have to hit the lowest common denominator. Finally, if there is any food-borne illness, there is going to be a serious problem (can you imagine a run on the restrooms over the Pacific). So safety first and if compromises in taste are necessary, so be it.”
There’s much more at the link. Very interesting reading for all of us who’ve had dietary disasters inflicted on us by the airlines. Turns out it’s not always their fault . . .