Had a great day at CDG last friday. Was pretty sunny but terribly cold. Maximum temperature of -2°C with a -14°C windchill due to the strong north-easterly winds.
Found how I should link images directly to a forum (still a bit of a flickr-noob), so I updated the original post with a little over 10 images. the rest can be found by clicking the link to my page.
It is possible to get to CDG by train, but getting to the spotting locations by public transport or on foot will be a pain in the a** ! CDG is one airport I would personally never do without car. Main reason being the need for a 4-step ladder at most of the locations.
It's a small effort to request the permit, so do it. If you are caught photographing without the actual permit (you need to have it with you, having one at home won't be enough) could cost you up to €250.