That is to say when the Flanker is extensively modified to take the massive force that catapaults act on the structure. Flankers structure aren't intended for that kind of force, so ski jump was suitable, though if catapault is to be chosen I would see that the Flanker should be undergoing serious structure change and strengthing. Personally the Flanker is too big and room consuming to be on a carrier. Its like F-15 launching of a carrier. But though the Chinese don't have anything between the heavey and light fighter category like the Americans do.