At first I thought that these might be 6x6 pictures from the likes of a Rolleiflex and cleaned up by the likes of the regular Adobe Photoshop, but they are universally 3:2 ratio, thus most likely 35mm, and therefore the sharpness and lack of grain is well beyond what Photoshop used to be able to do.
But, as you say, this must have been helped by AI and I see that Photoshop has had a superb AI version for a few years. There will be others.
These are by far the best quality pictures of these ships I've seen. I'm guessing they have been enhanced using the latest amazing AI image enhancing software. Thanks for sharing