These photos were made with the Sony RX 10iv.
They were taken at 600mm optical zoom in RAW and processed in Lightroom and Topaz Labs Denoise and Topaz Labs Sharpener.
I will post similar on 1200mm by digital zoom when I get new shots. They will be direct JPG as RAW stops with optical limitations. Be sure to under expose for about 1 stop as aeroplanes tend to reflect light like a mirror. For that same reason stop down your aperture at least by 2 stops from wide open regardless the max aperture setting of your lens and regardless of the 1 stop under exposure mentioned before. This aperture setting prevents for loss of detail due to utterly bright reflections.