I also wonder how much fuel is spent carrying fuel and if emissions wouldn't be lower if they would fly shorter legs on fumes and do frequent refueling stops.
* The final design of Habakkuk II gave the bergship, as it was called, a displacement of 2.2 million tons
* The small prototype built in 1944 on a Patricia Lake near Jasper, Alberta, confirmed the researchers' forecast that the full-size vessel would cost more money and machinery than a whole fleet of conventional aircraft carriers
* [Assistant Controller of Research and Development for the Admiralty during the Second World War] pointed out the large amount of wood pulp that would be required was enough to affect paper production significantly. He also claimed that each ship would require 40,000 tons of cork insulation, thousands of miles of steel tubing for brine circulation and four power stations, but that for all those resources (some of which could be used to manufacture conventional ships of more effective fighting power) Habakkuk would be capable of travelling at only 6 knots (11 km/h) of speed.
* the enormous amount of steel needed for the refrigeration plant that was to freeze the pykrete was greater than that needed to build the entire carrier of steel
* the crucial argument was that the rapidly increasing range of land-based aircraft rendered floating islands unnecessary
And that behemoth was required for a runway half as long as current civil airliners need.
Not to mention the size of aircraft carrier that would be required to land even a 737.
The various Pacific Islands like Hawaii, Guam, Midway, the Aleutians are effectively those "carriers" for ETOPS.
And as for that test: there is a reason it was left at the 'test' stage, it was deemed too risky.
It is amazing that they managed to land a C130 on an aircraft carrier at all, even more amazing that they did it 30 times or so without mishap, but it is a very, very long stretch away from being able to land a passenger jet and take off again routinely, what is acceptable risk for the navy would never fly (pun intended) for passenger service.
Really, I have no idea if this comment was in jest or halfway serious but there isn't any way passenger planes will ever land on any of the existing aircraft carriers. Width, Runway length, arrestor strength, inability to do cat launches with something that heavy and so on. It isn't going to happen.
63 meter wingspan for a 777 vs 40 meters for a C130, flight deck width of an aircraft carrier is about 80 meters so in theory that is possible but it would be pretty scary, I don't know of any airport where there is an obstacle the size of an 8 floor building sitting right next to the runway.
Though if you fitted a tail hook to a 747, probably some of that 747 could be said to have landed there. Maybe a few passengers too, and you could claim the fastest disembarkation speeds into the bargain. Turnaround times might suffer depending on the depth of the water.