President Biden's Special Envoy for Climate John Kerry was mocked by Republican lawmakers online after being caught not wearing a mask while on a flight to DC from Boston.

GOP lawmakers took swipes online at Kerry, who called the controversy "malarkey" in a tweet Thursday night, roasting the former secretary of state for his latest flying-related controversy.

JOHN KERRY CAUGHT MASKLESS ON FLIGHT, AMERICAN AIRLINES ‘LOOKING INTO’ APPARENT COVID VIOLATION

Sen. Tom Cotton, R-Ark., joked that Kerry is "not used to flying commercial" in response to the special envoy’s tweet.

Cotton also joked in a separate tweet that the "only surprise is that John Kerry is flying commercial."

He also told Fox News’ Shannon Bream in a Wednesday interview it was "better" that the climate czar "decided to fly commercial" instead of taking his private jet.

"I guess we can say it’s better that John Kerry finally decided to fly commercial as opposed to jetting around in Gulfstreams all around the world when he’s trying to supposedly solve the climate crisis," the senator joked in an interview with "Fox News @ Night." 

Rep. Lance Gooden, R-Texas, didn’t mince words in his review of Kerry wearing his face covering halfway. 

TOM COTTON SAYS JOHN KERRY HAS LONG HISTORY OF ‘NOT FOLLOWING’ RULES HE IMPOSES

"Ted Cruz removed his mask on a flight to drink coffee. Liberals wanted to lock him up," wrote Gooden. "John Kerry was caught not wearing a mask on a flight while reading a book. Liberals think he's an American hero!"

Kerry came under fire Wednesday after Tennessee Star reporter Neil McCabe posted the now-infamous photo of the special envoy given to him by a passenger on the flight.

Fox News confirmed that the passenger — who asked to remain anonymous — was on the flight via ticket stub. According to the passenger, Kerry took off his mask and let it hang from a single ear while reading a book in first class as other passengers boarded.

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The Centers for Disease Control and Prevention (CDC) under Kerry’s boss, Biden, issued a mandate in January that went into effect at the beginning of last month, which states that individuals "must wear masks that cover both the mouth and nose" while traveling on public transportation and while at a "transportation hub."

Kerry has faced scrutiny over his family's ownership of a private jet. The former secretary of state also took a private jet to receive an environmental award in Iceland in 2019, Fox News revealed in February.

Kerry defended his decision to fly private when asked about it in Iceland, saying: "If you offset your carbon — it's the only choice for somebody like me who is traveling the world to win this battle."

Fox News’ Sam Dorman contributed to this report.