All this advice seems like such a lot of hassle; vibration from holding it against the airframe would certainly cause the problem but otherwise, I think you simply need to get a different camera, and to name & shame the one you're using!
I use a Fujifilm/finepix 4700 and frankly it's perfect. I've taken hundreds (nearly thousands!) of photos inflight in lots of very scratchy and dirty old rental aircraft, in all weather and times of day, without having to give a second thought to whether I'm holding the camera near or touching the 'glass' or worrying about settings and stuff. Don't even need to hold it particularly steady. It does everything automatically, I can just pick it up, take aim and click, with no delay, and every time it grabs an awesome photo. Everything always seems to look even better when I download the images than I remember the scenes in real life.
My first digi camera was supposedly 'good' too but actually it was useless, very easily took blurred photos so I just got rid of it on yahoo auctions, managed to get back just a tenner less than I paid for it
