While I admit they are very similar, I can see differences.
Length of tailpiece
Length of wingtips past "risers"
Fatter body (the spaceship, not the girl :) )
Due to the angle, the nose could be different (no beak) and ridge around eyeline, but can't tell
Here's what the photographer said about it:
The space ship would be the fruit of the tree of knowledge and the girl, the fruit of the tree of life.
The space ship could be made by Mick Milligan, a jeweler at the Royal College or Art.
http://www.bobseidemann.com/blind_faith_doc.html
I'm going with he did in fact follow thru and had the jeweler make the spaceship, taking the above visual points into consideration. Still doesn't answer why a spaceship would need wings, maybe they're scientologist and believe in the DC8's.
That was not a model spaceship, rather it was a 1956 Chevrolet Bel-Air hood ornament.