Requiring a health declaration card sounds nice in the esoteric, but since a high number of persons who have the disease are asymptomatic, not sure it's terribly useful. Even requiring a negative test is not terribly helpful, unless it was really close in time to the flight. And there is simply not enough testing capability, even now, to give everyone a test who wants one. Either way, in order for the island to survive financially, they will eventually have to open flights to Europe and the US and Canada.