Hap Arnold was looking for a way to provide heavy maintenance close to the fight in the very mobile Pacific war. They hit on the idea of a floating factory. Six Liberty Ships were fitted out (the "Generals") with all manner of shops, from machine shops, to oxygen refills, to carburetors, etc. Each ship had two or three helicopters and two DUKW's to ferry people and parts. The Generals could handle B-29's and P-51's, while the smaller ships (the "Colonels") handled fighters. They were also heavily armed with AA weapons.
The crews were a curious mix of Air Force mechanics and Army sailors, drawn from the Merchant Marine.
I found a very interesting unit history of the MG Dargue (2nd Aircraft Repair Unit - Floating).
http://www.cbi-history.com/documents/2nd_aru_history.pdf
I thought the plane repair ships were an interesting concept. Another example of the astounding accomplishments that were the epitome of the American Way of War. An accomplishmennt that was a footnote in a gargantuan war effort that could not be duplicated by any other nation on earth. They simply did not have the technical or human resources available, much less the spare ships and weapons for them.
“Let’s take a run of the mill merchant ship, of which we have hundreds, and turn it into a high tech state of the air art floating aircraft maintenance shop, and we’ll arm it to the teeth, too. How many of them? Oh what the hell, let’s start with six and we’ll go from there. Why? Because we can, of course.”
Again, it’s the American Way of War. Bruce Catton documented how it began with the Civil War, when before the Battle of Chancellorsville, the Commandant of the US Military railroads Hermann Haupt figured the line to Richmond would likely be damaged by the fighting. Just to cover for eventualities, he ordered up 10 miles of railway iron to repair the track as needed. There was not 10 miles of replacement railway iron to be had in the entire Confederacy. For the Union, it was the spare change of a military operation.