American Airlines is investigating if U.S. climate envoy John Kerry broke the rules after he was photographed on a recent flight without a mask. In a statement, American Airlines said, "Masks are required on board our aircraft" then added, "The crew did not observe Secretary Kerry without a mask, and they were not alerted by other customers to a non-compliance issue. We continue to review the matter." Kerry himself responded, "Feels like there's some St. Patrick's day 'malarkey' afoot on Twitter. Let's be clear: If I dropped my mask to one ear on a flight, it was momentary. I wear my mask because it saves lives and stops the spread."