Airlines put a tremendous amount of thought into their liveries. Well, some do. There are design firms that specialize in working with carriers. Landor Associates is the most notable. Another is Onoma, Inc., in New York. I once interviewed the Onoma designer who came up with Continental Airlines' latest colors (see article below).
I realize this is self-promoting and all, but I wrote a whole series of online articles about air carrier liveries and identities, a portion of which also appears in in my book. Below are the links to the articles, which anybody with an interest in livery design might like to read. The last of the four articles includes a "report card" grading the US majors colors.
Note to moderators: this is on-topic and I do not make so much as a penny for sharing these:
Airline identity: Logos and Liveries:
Slogans, Centaurs, and "touch lines"
From kiwis to salt packets: The yin and yang of airline identity
Mourning the cheat line: a logos and liveries report card