Published March 13, 2021, 12:12 AM Cruise ships, just like airlines, are down these days because of the pandemic. People around the world are not travelling because of the strict requirements at airports about visitors possibly carrying the coronavirus. We remember only too well that our first two COVID cases in the Philippines were a visiting Chinese couple in early 2020. At the start of the pandemic, two cruise ships were compelled to stay away from ports because so many people on board had become victims of COVID. Then, there was the American aircraft carrier where so many crewmen had fallen ill. The shipboard infections must have been spread by the air-conditioning. But it was not known at that time that the virus traveled easily on streams of cold air blowing out from air-conditioning units, as well as in the very breath of persons standing close by.