To emphasize the fact that the name of the airline (or phone bill customer or appointment book owner) is required, it should be provided in the URL path and not an (optional) URL parameter.

So, in the dictionary example, there should be a "name" for the dictionary.

I might also want to create a Dictionary class in the out-of-the-box example so that it is more apparent that it must be morphed into the airline (or phone bill or appointment) as part of the implementation. All of those Maps can get confusing.