As the last four pictures in the pictorial guide section show, there is a (blocked) gate and tunnel that heads directly towards ironforge, although the tunnel does not as-yet quite reach the city.
The airport area is pretty big, and at the far end of the area is a blocked tunnel that appears to lead towards Ironforge. At the other end is a Griffon Roost. There are NPC's and an Inn style building. The NPC's are all copy-n-paste ironforge guards and gnomes from the Salt Flats Racetrack. Nothing is functional at this point, but all signs point to someday this will be an area we can get to legitimately.
The purpose of "Ironforge Airport" is as yet unknown. While the scenery may very well be nothing more than "flyover eye-candy", there are several peculiar characteristics that might point to a more complex future purpose.
The Ironforge Airstrip lies on the eastern slopes of Mount Ironforge and contains planes, runways, an NPC battle on a lake, finished buildings, blocked tunnels and even a Gryphon Master. The area has become increasingly difficult to reach with each game patch.