The idea being putting the hangar below the flight deck, as usual, but straddling the two hulls. Few carriers have a hangar extending below the waterline anyway and you want the section joining the hulls to be as tall as possible to increase girder strength, so this seems sensible. That said, I think the advantages start to diminish when you think in terms of weight/displacement--the hangar and deck aren't any lighter for their size on a catamaran vs. a monohull, and the skin and structure are likely heavier for the same displacement. For the catamaran to be worthwhile you need gains in propulsion to offset the more complicated hull.
The biggest problem with a catamaran might be excess primary stability--I think catamarans tend to have a pretty snappy roll, which would be rough on flight operations in high sea conditions, particularly for smaller ships.
The idea being putting the hangar below the flight deck, as usual, but straddling the two hulls.
Maybe, even so, I'm still nervous about what might happen, say, in case of things like ramp strikes. I guess you'd actually be less likely to damage the rudder or propulsion with an aircraft falling well below flight deck level and striking the stern on landing, but if it hit the rear of the hangar deck, I could imagine a chunk of the hangar deck falling away, and, with nothing below it, falling into the sea with any equipment and personnel that happened to be there.