Andrew, just do it and don't bother asking. Some ignorant CC member who doesn't know what he/she is talking about will most probably say "best not to...". I've always flown with my big flashy DLR in my lap (when I have a window seat) and its nobody elses buisness. When I'm not using it I'll put it down by my feet. The thing with telephone cameras is that they look like a telephone and people probably assume you are using a telephone, whereas a camera is camera and people/CC don't give you a second thought as so many people are actually using one. Look at this from the cnn website, they have an i-report page and one of the current assignments is pictures 'from the airplane window'.
Airplane window photos: News & Videos about Airplane window photos - CNN iReport
Keep clicking on the 'show more' and hundreds of photos will keep popping up. There are some amazing photos there, so you can see what you would be missing. I have one in there somewhere called 'welcome to London 2012'. If photographers had to ask, some of the worlds great photos would never have been taken.