Here's a 'stream of consciousness' based on colour and photography, not knowledge of jet colours!
The white is very overexposed in the 'non-grey shot' - the photo has been changed digitally. The sky colour doesn't look at all natural either. On the other versions detail is not lost as much on the tail. The flight suit colours look different too, they are certainly toned slightly more yellow/green in the 'whiter' shot.
The unframed shot could be interpreted as a digitally 'cooled'/processed version of the framed photo. The grey therefore looks a little blue - cooler. The signed framed shot looks to have the 'correct' warm colour balance for direct sunlight - given the shadows on the aircraft, aircraft in the background and the crew faces, and the long shadows in general, a lowish sun with warm light produced the colours in the 'original' shot.
The exposure in the 'framed' shot prioritises the aircraft, so the crew look a little underexposed as a result.
Looking at the exposure of the crew in the 'overexposed shot' it may be that in order to make the humans look better, the plane looks worse!