This is of interest to me as the location for partially terriforming a small (size of Australia) portion of Venus and the 11 kilometer peak a few hundred kilometers from the North pole of Venus. A snow fence with a radius of about 2000 kilometers surounds the pole and the 11 kilometer peak. Fence circumfrence about 12,566 kilometers catches dust, raising the elevation. Portions of the fence need to be moved or replaced anually. In about 10,000 years, the area inside the fence may reach an average elevation of 11 kilometers, with some parts perhaps 20 kilometers. The high elevation cools the platau to perhaps 300 degrees c. Many sunshades in the upper atmosphere and/or orbiting just above the atmosphere cools the platau to about 200 degrees c. This allows it to rain sulpheric acid on the platau. Just before the first rain falls the lower portions of the platau are covered with an impervious layer, so the acid does not sink below the surface of the platau which is likely still hot enough to boil sulpheric acid. Over about 10,000 more years nearly all of the sulpheric acid in the atmosphere of Venus will be trapped in artificial acquifers of the great polar platau. Venus can then be bombared with ice comets, which will permit real water rain to fall on the polar platau. With a new giant sun shade which is transparent only to photons best for photo synthesis, we can now grow crops on the highest elevations of the polar platau. Genetically altered humans can tend these crops naked except for an oxygen face mask. Since the atmosphere is still about 90% carbon dioxide, a prothesis is need to remove carbon dioxide from the blood. It may take a million years to get the carbon dioxide of all of Venus below 1%, even with extensive agriculture on the great polar platau. There are numerious ways to hurry the terriforming process, but most require enormous resourses. More details later.
Please embellish, refute and/or comment  Neil

If your aircraft cariers ect have an average density of more than one kilogram per cubic meter = 1/1000 th the density of water, they will float below the cloud tops of Venus where the sulpheric acid clouds are found, and little solar energy is available. CNT = carbon nano tubes may permit a low enough average density to stay just above the cloud tops which I agree is ideal, except the habitats will fall if large quantities of carbon dioxide leak in. I agree linking them (with air locks) makes falling very improbable as it is very unlikely more than one would have a bad leak. Floating cities high in Earth's atmosphere have much the same problem, except the inhabitants might survive the fall of their habitat to Earth's surface.   Neil

If we are talking that far in the future, 90% CO2 isn't a big problem. We should have artificial blood by then that is self propelling. The heart and lungs can be replaced by a artificial blood refueling station using compressed air. We can therefore take in all the air we need for the day in one long breath each morning.