That is a difficult question to answer and depends on so many different variables: lenses, tripods, f stops, the list goes on. What I did notice on the first photo you link to is this. Look at the underside of the aircraft where it is in shade. You will notice a very thin white line between the shade and the blue sky. That line is possibly an artefact caused by over sharpening in post processing. These artefacts appear at the junction between high contrast areas. It may also simply be a reflection of the sun hitting the metal, however I doubt that.
That does not really answer your question as these photos were taken by professionals with no expense restrictions. What lenses do you use? Do you use a tripod? What f stops do you use and under what circumstances? If you are consistently not getting sharp photos, then it points to a problem with your equipment or your understanding of photography, unlikely as that may seem to you. I have no problems getting sharp photos if I use a good lens and shoot according to the existing conditions. I also fail miserably but it is always my fault.
Sony A7, A850, A77, A700 || Sony>> 70-300G, 28-75 f2.8 SAM, 16-80CZ, 50 f1.4, FE 28-70 OSS, FE 24-70CZ f4 OSS, LA-EA4 || Minolta>> 300 f4 G HS, 200 f2.8 G HS, 100 f2.8 (D) Macro, 50 f1.7, 28 f2.8, 28-135 f4-4.5, 70-210 f4, 500 f8 Reflex, TC x 1.4 HS, TC x 2 HS. || Sigma 21-35 f3.5-4.2. || Tamron SP 24-135.