Jumpseater, job done. can I have my cheque now please?
Something sounds awry with HDs setup. A file might also prove useful in the Exif settings, A great boon for digital photographers. The shooting data is kept with the file and so I should be able to tell at least something about the settings, though a Canon user would read more through their dedicated software I am sure. I learn a lot from these settings and you can often see where a shot went wrong through technique or a camera issue. Believe me, the in camera settings, especially for JPG users, are so sophisticated that it is easy to miss out and for users to feel that they have taken a backwards step. Part of the ultimate flexibility that you have with a DSLR, but also, until right, a source of concern for any user that has just parted with spondooliks for something they expect to give better results.
I think that on the airliner shots that I have seen, then something may well not be as it ought. A common problem is one of front or back focusing, where the camera AF is slightly out of kilter and is in essence confused by what it sees, the assumed focus being a bit in front or behind. I can't actually see this so much as the A/C shots should be near infinity and not so badly affected. Ultimately, it might be worth letting Canon look at this, but I could help narrow it down a bit with a few RAW and JPG files. The EOS20D is crawling around the bazaars and is known for producing high quality shots. I think that you don't have proper spot metering on the 20, but centre weighted should help those shadows a bit. HD, don't lose heart. we might be close to identifying a particular problem here and nobody will be happier than me.
Conan