Hi Patrick.
First of all i would like to say welcome to ASB and hope you have a good time here.
About your pics. They are quite good, but i do have some remarks.
Try photographing in RAW, this will improve your options with Photoshop bigtime. Try to do some fieldwork befor you go out to an airshow, see what your camera does or doesn't do... Try to set it on different settings etc.
Keep in mind that you need a shutterspeed of about 250 or 320 for Propellerdriven aircraft (warbirds), 400, 500 for aerobatic aircraft (Extra 300, EDGE 540, etc.) and about 1000 to 1250 for a Jet).
Your ISO was a bit to high in my opinion, this result in Image noise (the little colored pixels you see when you maginfy your pics on the PC screen). This can easily be removed with photoshop also.
Have a look at my pics and let me know what you think. My pics are made on a tight budget. (what means that none of my lenses are more than 200 dollars)...
My AlbumWhat i also have to say is: Be proud of what you make. You always can learn from it and how to do it in the future... I sometimes go back in my archive and see what kind of pics i made that i now think are horrible, but then i was very proud on them...
Grtz and keep on shooting,
TG1984