I think there is some difference between a real plane spotter (ultimately more interested in "collecting" as many aircraft types, versions, names of companies, etc. as possible) and photographers who are much more concerned with composition, colors, etc. It's the difference between just recording what you see and actually photographing. You can remove a small color cast when editing photos, and it may also be advisable to work with a calibrated computer monitor, but a tight crop is an issue that you have to solve while taking the photo.
I don't really mind the background and I don't think you should emphasize clouds or darken the green bossage, that would take too much attention away from the plane in my opinion, what I did do is make the bossage a little more horizontal and add a bit of motion blur to suggest speed. The aircraft must have space and that is why I added a large section at the front near the nose and a little extra space at the back. What I do find important is the shadow (I have lightened it a bit) under the wing and the slightly too light rear part of the aircraft and the blue color at the bottom of the aircraft. These are all very small changes that may be barely visible, but do contribute to the overall experience.
Made a little edit of your jpeg image, but not in Affinity, of course this is nothing more than my personal opinion, not every person is the same and not everyone will think the same about everything. Let me say that the basics are not bad at all, on the contrary, photography is really nothing more than learning, a lot of trying and finally the experience you collect over the years, good luck with your plane spotting and photos.
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