Well, sort of. As it turns out, the thing that makes airline food so tasteless is the noise on an airplane, which apparently limits your ability to taste sweetness and saltiness. (This is also why food tastes bland when you are eating it next to an explosion, or a person yelling in your ear.)
Researchers had a group of participants eat foods with either silence or loud white noise on headphones, and then rate the food's sweetness, saltiness, and crunchiness. Food eaten while noise was played on the headphones was consistently rated less sweet and salty—though, oddly, it tended to be rated more crunchy.
So, there you have it: Airline food tends to taste bland because airplanes are so goddamn loud. Because of this, airlines season the hell out of it. (Apparently, NASA also gives its astronauts strong-tasting foods, like those dehydrated ice cream bars, I guess.) Maybe, instead, they should turn off the engines for, like, 20 minutes or so while everyone is having their lunch.