President Joe Biden's climate czar John Kerry was seen maskless on a plane despite requirements that passengers don face coverings, sparking an investigation from American Airlines.
American Airlines said that masks are required on board its aircraft and that it was probing the situation.
In February, American's COO David Seymour said the airlines would mandate masks to align with a Centers for Disease Control and Prevention directive that was issued in accordance with an executive order from Biden.
“Our mask requirement has been and will continue to be a critical component of our comprehensive effort to protect the health and well-being of our customers and team members during the pandemic,” he said in a statement. “This federal mandate will provide additional support to our crew members who are working diligently to enforce our policy and further reinforce the safety of air travel during COVID-19.”
Biden has repeatedly exhorted Americans to wear masks, even if they've been vaccinated against the virus.
Kerry, the special presidential envoy for climate and a former Democrat presidential candidate, said in a tweet that there appeared to be a misunderstanding.
"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. It’s what the science tells us to do," he wrote.
"If five minutes is 'momentarily,' he's correct. Not sure being in a plane without a mask for five minutes is excusable," the passenger said.
American Airlines told the outlet that no crew members saw Kerry without a mask and no fellow passengers alerted crew to what was happening.
"We continue to review the matter and we are reaching out to Secretary Kerry to underscore that all customers are expected to wear masks for the duration of their trip," the company said.