The previous poster was on the money. It's mainly about protecting the airline's trademark and goodwill; to a lesser extent, they may want to ensure people stop at their website to maximize referral revenue from hotel and car rental companies.

On the other hand, it sounds like a particularly useful app, and perhaps, by making it a general use application (i.e., not specifically targeted at Ding) you can guide it through the various IP law issues and market the bugger.