Why not just put it in the freezer?
Or walk down the street to the gas station and buy a tub? 
To reiterate from the original post:
Quoted fromhttp://www.vectorsite.net/avf4u.html
Late in the war one squadron in the Palaus found the action slow, and to stave off boredom the ground crews rigged 19-liter (5 US gallon) cans ...
Bored military guys find some of the strangest things to occupy themselves. I'm generally not that big on feelgood stories, but I find stories like this oddly uplifting for some reason. Maybe it's the simplicity of the things they do and did. Maybe it's the contemplation of the thought process it took to go from 'we fly airplanes in war' to 'let's rig up something on the plane to make ice cream'.
In any case, it made me chuckle, and I'd definitely want one on my plane. I fly high enough, I would probably qualify to make it.
Wiley.