As you can see, most of the suggestions involve information that can not usually be found on the airport's official website. But given that, a link to the airport website or other websites with information about specific airports would be helpful.

In order to keep your site manageable, in general I would recommend links to sites where information can be found rather than re-listing everything about every airport. For example, ground transportation, airport maps, airlines serving given airports and similar information can easily be found elsewhere. It's the more obscure but equally important information posters have listed above where your site could be extremely helpful.