Ryan, nice photos, get a copy of Paint shop pro, theres plenty of free evaluation copies on the net, I use PSP 7 for all my sim work or photo editing, there are better photo editing suites around but PSP 7 is free and a good basis to begin with, theres an option in there to sharpen images, works very well. It has two sharpen modes, sharpen and sharpen more, three sharpens equal one sharpen more.
Another application I use is Infraview, also free, this also has a sharpen mode and equals two PSP7 sharpens, where Infraview really shines is in the jpg compression for internet images, it has a much better compression algorithm and images are much crisper after resize and compression, its also free I believe.
One good tactic with aircraft is to shoot at maximum image size and a slightly lower zoom level then cut the part you want after wards, the lower zoom level will increase your aperture and probably help reduce camera blurries. Try also to keep your ASA setting as low as reasonably practicable, the difference between 100 and 200 ASA is quite dramatic, especially at long zoom levels or lower aperture settings.
Must confess I'm looking at the 28-135 IS USM lens and a Canon 40D, would love the 24-105L IS USM but funds are not forth coming, will have to send the kids out chimney sweeping or something

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Good shots, keep them coming.
Attached a local snow shot from last week, no aircraft, but taken with a simple Canon A620 point and shoot, though it does have full manual control and is quite in depth with almost as many options as a DSLR, just the optics that let it down, the image has been midly processed in PSP to sharpen one stop, contrast +5% and thats it. full aize image can be seen here
http://homepage.ntlworld.com/mickoo/IMG_5868.jpg
Where point and shoots really loose out is very fine detail, like the over head power lines to the left, any more sharpening and these will break up and look like very bad aircraft antenna in FSx with no AA.
The morale here is that you dont always need the most expensive gear to get half decent photos in moderate to good optical enviroments.
Kindest
Michael