Giger's imagined the original jockey to be about twenty five feet in height and I think I read that in Giger's Alien
Here is the reference, HR Giger "In his seat in the centre of the turntable is the pilot, eight metres (26 feet) tall." (Giger's Alien p34, 25 July, 1978, ) Did he mean what he seems to have said?
I remember the reports out the Engineer being 9 foot tall appeared in Empire.