The IS in the 16-35IS would definitely put it high on my list for a helicopter shoot – the IS will definitely work more in your favor than would a larger aperture in a different wide lens. However, have you shot from a helicopter before? I've never shot from one professionally, but I have had the chance to go up a few times with cameras on various trips, etc. I always seem to find myself at the longest end of whatever lens I have mounted because things are definitely smaller than expected once you're up in the air. Of course, that entirely depends on what type of shots the client wants, the location of the hotel, and how close the pilot is prepared and/or allowed to get.
I have yeah, a couple times now and you have me thinking about it being too wide on a full frame. Maybe the 24-70 i have will be better or even the 70-200 f2.8II IS. I guess it was an excuse to get a new lens 




