Some years back I had an interesting conversation with my wifes uncle, who had been a Spitfire pilot late in WW2.
I was telling him about an anti-g suit displayed at Duxford, used in the Mustang, and how surprised I was that they had them.
He said that he had trialled one and that it was water filled.
As mentioned by a post above, his mates were not particularly kind to him when he came back from a trip where they encountered 109's and one of the bladders had burst!
Amazing how nothing is new in aviation!
lsh.