Welcome to an addictive hobby!
Lucky you having contacts at Canon.
I'm new to this as well and I've only got one photo on the DB
but that is with a Canon 300D so the 450D will be excellent.
For more ideas on composing shots and what is required for A.net check out the discussion below;
New To The Hobbie (by USA1890 Feb 21 2008 in Aviation Photography)
and specifically the useful links in this response;
As the guys said make sure you shoot with the Sun behind you where possible. (Lots of practice and you'll figure out how to position yourself for various lighting conditions.)
I like the pics of the Hornet and PC9 ... 'artistic' angle but not want A.net wants ... they like things being level! The Herc Bird is ok because it is banking.
[Just did a quick search and there is only 1 RAAF PC9 pic in the DB
If you are ever in SYD
happy to show you around.
Good luck and hope you have fun with the new camera.