A airline can hire a firm to Statistically determine frequent fliers propensity to use varies products, such as in flight movies, music or drinks.
By combining a zip + 4 Census (The big U.S. one) and a Claritos study, a marketing firm can determine with considerable accuracy what products (down to exact types of movies, music, drinks, and meals) a group of people would prefer. This group is of course very identifiable, us. The frequent flier, which the airlines already know everything that is statistically relevant, i.e. address, zip + four, spending patterns, and travel patterns.