I usually only use PTGui's "Project Assistant." After I import the 26 or 25 photos (
Mavic 2 or
Mavic 3), shot with the drone in "spherical" panorama mode, into PTGui Pro, I set up the panorama using a lens at 10.3 mm rectilinear with a 2.7x crop (
Mavic 2) or 12.3 mm rectilinear with a 2x crop (
Mavic 3). Then I align the images. [This is usually sufficient but if a control point ends up on a cloud or boat or automobile (rare) then I may have to adjust control points outside of just using the Project Assistant.] I then use the panorama editor where I check that I am making an equirectangular 360x180 panorama; that I am blending with exposure compensation and optimum seams with zero overlap. It is here that you can also fill missing areas, like the overhead sky, which gives an approximation that matches the upper seams of your sky photographs. [Note that you could provide a sky shot from another camera, but it wouldn't be from the same point of view in the sky and will be extremely hard to match.] I then yaw so I am facing a desired point (which becomes the middle of the default panorama), adjust pitch and roll very carefully to get a level straight horizon (usually only tenths of degrees), and then either use "tone map" or "fusion exposure" and adjust to taste. Finally, I choose the desired output file type and create the panorama file.
I am sure you could easily use this procedure with the
Air 2S by making adjustments to the parameters mentioned. The software will extract lens information from the metadata of the photographs that will be useful as a starting place.
After you have used this procedure to the point you are satisfied with it, simply save it as a template file from within the file menu of PTGui. I have done this and it works fine for a similarly-shot panorama.
While some find this software pricey, I think it is very good at its job, while allowing you to make detailed changes as needed in stitching (although that can be time-consuming). I rarely have to adjust stitching. I also recommend you use raw files, save panos to jpgs for convenience, or tiffs (without alpha layers) at 16 bits for further processing with photo software. I use Affinity Photo to color balance, adjust contrast further, enhance clarity (helps remove fog or humidity) and sharpening. I also use FCP to make movies where the point of view "flies around" within the final image.
I hope this helps.