The art and voodoo science behind airlines' amenity kits

With the airline business relatively stable and momentarily (if thinly) profitable, carriers can fiddle with frills like the amenity kit they offer as perks to their big-ticket customers in premium classes. But like so much of the airline industry, the logic of the kits is more art than science, more voodoo than research..."An amenity kit can cost an airline anywhere from $4 to $30 a unit. No one agrees whether it's great for brand identity or it's something that we're afraid to get rid of because we've always done it."

Passengers are at least as divided as the airline industry. Some glance at the bag when they get to their seat..and then ignore it. Some use the products inside—socks, eyeshades and ear plugs are most popular, suggests Delta's Wilander—and leave the rest of the contents and the case itself behind. And some are obsessive collectors, taking not only their own bag, but also scooping up any that fellow travelers have left behind.