US aviation authorities have launched an investigation after two pilots were heard barking and meowing at each other over the radio near one of the country's busiest airports.
The bizarre incident occurred close to Ronald Reagan International Airport in Washington DC.
One pilot could heard saying "meow" into the headset before another responded with a "meow" of his own.
The pair were immediately told off by an air traffic controller at the airport, who urged them "to be professional".
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However, the rebuke only encouraged the pilots to escalate the animal noises, exchanging even more barks and meows.
The controller then jabbed: “This is why you still fly an RJ [regional jet].”
But now the Federal Aviation Administration (FAA) has launched a probe into the exchange, which is believed to have occurred on Sunday.
The authority said it was looking into verifying the audio and uncovering the pilots' identities.
One pilot could heard saying 'meow' into the headset before another responded with a 'meow' of his own
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Under aviation law, pilots are banned from having non-essential conversations while flying below 10,000 feet.
Dennis Tajer, a spokesman for the Allied Pilots Association, a said it was not the first "meowing" incident he had come across in his career.
He said he has previously overheard similar animal noise exchanges on the "guard" frequency.
The frequency is typically reserved for emergency situations.
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The bizarre incident occurred close to Ronald Reagan airport in Washington DC
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He told ABC News: "It's not entertainment, it's a serious frequency and it has a serious purpose.
"Anything that contaminates that with idle humour or any kind of schtick is not received well and it should stop."
Addressing the meowing aviators directly, Mr Tajer said: "For the few individuals out there that do it - stop, join us, stay safe and we'll keep that frequency sacred and protected."
In a statement, the FAA said: "FAA regulations prohibit pilots from engaging in non-essential conversations when they're below 10,000 feet altitude.
The FAA said it was looking into verifying the audio and uncovering the pilots' identities
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"Conversations must be related to the safe operation of the aircraft.
"The FAA investigates all situations where pilots may have violated any regulation."
Ronald Reagan is home to the busiest runway in the US and is ranked among the country's 25 busiest airports.
According to Metropolitan Washington Airports Authority, the DC travel hub sees almost 25 million passengers travelling through every year.
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