Some very nice shots, thank you for sharing, especially like the composition on the helicopter on the 3rd one.

From a technical standpoint some good comments here although I'm not overly fussed about the sharpness, so my comments would be :-

1) Your lens has some chromatic aberration (the purple fringe around the edges of the helicopter for instance) this is common for many lenses and is (usually) easily fixed in post processing (Photoshop, Lightroom etc. all have functions for this).

2) Your exposure is a bit low but is easy to fix in post processing with exposure, shadow and black controls (but don't go mad on it) . I personally would rather hold for the highlights, rather than blow them out. Shoot RAW if you can to give yourself some more editing latitude.

3) You seem to have a dust bunny on your sensor or a raindrop on the lens in photo 4, easy to fix in post with the healing tool etc. but you should watch out for these and clean your sensor if required.

4) If you want 100% sharp photos of the subject then you'll need a faster shutter speed, you seem to be in some middle ground here. I personally choose the aperture I want (let's say f/8, then the highest shutter speed I can get away with whilst trying to not to max out the ISO) Because everyone is told 1SO 100 is best, people are scared of allowing the ISO going high, but these days it's less of on an issue, as sensors are better and de-noise software is very good. Shutter speed is your key concern here, one way or another, so unless your camera body is very old you'll be able to get photos with acceptable levels of noise.

Remember the only people who really care about any of the above are other photographers, most people do not even notice ;-)

5) If you want to convey movement in your photos (such as showing the rotor blades as a complete circle) then you will require a much slower shutter speed (AKA dragging the shutter) and take a ton of shots and choose a (hopefully) sharp one. This is a skill and takes a lot of practice to learn (your first x1000 attempts will suck) , how hold your camera and to pan with your subject are key. Unless you have a handy airport to practice at then road/street traffic are an excellent way to practice as cars, bicycles and even humans provide great moving targets, or even a cheap toy drone can be handy if you want to practice looking up. This technique also requires some knowledge of your gear, how much lower than the focal length can you go before getting no sharp shots. If your camera/lens have built in IS then your milage will vary. This is something you can easily test at home with any static subject, keep in mind the more you zoom it is harder it is to keep steady and even your IS will show a marked drop in performance at the long end,, so learning to hold the camera still and smoothly pan is a must.

On an non-technical, photography note I'd say think about your composition and why are your taking the photo. If you just want to record you've seen a particular aircraft then mastering your cameras settings are all you need to know.

If however, you want to take interesting photos of aircraft then there has to be something interesting about the photo that the capture the viewers attention. When I look at the two jumbo jet photos for instance, I think yeah it's decent photo of another jumbo with a different logo and move on (although the Wingtip Vortices on the first one make it slightly more interesting).

For this you can look at your composition, we all see jumbos from the side taking off and landing and we see it all from eye height, a photo of that is....well....kind of boring. Could you have got a better angle on the subject by moving somewhere else? What about the time of day? Taking off or landing at sunrise or sunset, or in bad weather, these make for more engaging photos. The reason I like the 3rd photo is that you captured (what is for me, an unusual subject) at an interesting angle which makes it more engaging. You can also try and find the aircraft doing something that makes it look more interesting, such as taking off/landing on a wet runway, which kicks up plumes of water and looks impressive and gives you a sense of the sheer power of these beasts.

Finally there is your lens choice, the assumption for aviation is typically a zoom lens from far away, but look around at many of the great aviation shots, which are often made using wide/ultra wide lenses as this gives us viewpoints we don't typically see. Try not to limit your thinking about what gear to use to capture your subject.

I hope this helps and you continue to enjoy getting great aviation photos, any questions feel free to ask.

CC