Speaking from a avid plane spotter experience, you can use camera or camcorder within the terminal common area.
If you point your equipment towards staff entrance etc, or record a single location for prolong period of time with no particular subject in view, then they will tell you off or even escort you to their security office.
Using of camera or camcorder around the perimeter is strictly prohibited and may also send you into their security office as well. I've been there done that. :bsmilie:
I was on a company trip to US and my colleagues had already walked through the metal detector and their barang barang went through the scanning machine. So when its my turn, my colleague on her camcorder and film the rest of us who were walking through the detector.
As it is a sensitive area, the guard all went on high alert and 1 guy (supposedly their senior) came to her and told her to delete the portion of the footage. Funnily, as it was a company camcorder, no one knew how to delete the footage.
We re-assured the guard that we're a sg listed company and he let us go.