Airshow Pics

I'm a newbie not only to DGrin but also to having a non-point and shoot camera. I just picked up a Canon S1-IS last week and I took it to a local airshow last weekend. I'd appreciate any comments you guys have for me while I'm learning the ropes.
http://daveorama.smugmug.com/gallery/145698
http://daveorama.smugmug.com/gallery/145698

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Comments
Great shot,
Oh and welcome to DG
gubbs.smugmug.com
Yeah, these are the shots striaght off the camera, I haven't had time to play with them in Photoshop. I'm sure some tweaks could make them look better.
Someone commented to me that the shots were pretty noisy. I used ISO100 just because I didn't know any better. Would ISO50 have been cleaner? Or is the noise a function of something else?
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
Maybe I can sneak in another newb question. Does the f/ also affect noise and clarity of the image like ISO does? I really like some of my shots, but most aren't tack sharp. I guess that could just be the combo of the planes screaming by at 300+mph and the IS tryng to do it's job...