I am sure the airport as well as the margalla avenue will result in increase in prices. However, fortunately for D-18, it is also the site for another major infrastructure project which will immensely benefit the adjoining societies i.e. The Sangjani Interchange. While most of the other projects in Zone 2 have been facing various problems, the one thing that is going right is this project, which is progressing at a good pace and might be ready even before its deadline, InshAllah.
Once complete, it will be only the 2nd interchange in entire zone 2 (& only 1 of 3 for entire isb) after tarnol, providing direct connectivity through the motorway, and will immediately lead to a rise in demand and prices. So if you are holding any property in this area, its definitely a hold for now.
@Saadi_Aquarius. Sir if your opinion is based on quality of development, then I agree that there are places with much better development standards. But I also believe location and access have an equal, if not greater role, in determining real estate prices. Specially, if the future projects announced by the govt. Including ring roads are ever completed, the motorway alongwith the ring road network will become the jugular vein of Islamabad.