Good efforts for your first attempts at aviation photography.
The first thing that I noticed is that the uploads are rather too large. Unless you are a real expert in editing, with great quality shots, I would strongly advise that you upload smaller images - for example 1024 x 683. These photo sizes will make the image look better in many respects - for example, sharpness.
The standards are very high here, as I am sure you already know. So for your first attempts I would go for something relatively 'easy'. What I mean by this is shots that are not going to test the screener for their view of things like motive, or exposure. The South African shot is somewhat complicated by the fact that it is a ramp shot, and often these are rejected for the non-airplane stuff around in the image. Your shot is not helped by the fact that the plane is facing away from you, there are stairs visible and there is a bit of 'dead' space above the fuselage. Also, the quality on that image is not great - if you look under the wings there is a lot of grain. So, as well as issues like motive and the shot not being centred, this one suffers with quality issues.
Now I do prefer the Kuwait shot. The light is not great, but I think the motive is much less contentious. I think the crop would be improved by bringing in the left edge closer to the tail, and cropping out that dark bit at the bottom. The lighting can also be improved on this in editing, I think. I reckon this one can be improved a lot by editing it differently.
I would be very happy to try to edit that shot for you if you would like, and I can take you through what I do. Just contact me through my profile. Also, I would be very happy to discuss any other details you would like.
All the best.