Revealing mistake: When the toy aeroplane, which is supposed to be remote-controlled, attacks Wonder Woman, in a closeup shot you can see the wires which are actually controlling it.
Revealing mistake: Wonder Woman lifts the rear of the toy maker's van. During the pan from the rear wheel to Wonder Woman you can see the jack holding the van up.
Answer: The transformation twirling was invented for the 1970s TV series only, to explain her quick change from Diana Prince to Wonder Woman. However, it would have been nice to do a little spin homage in the movie.