What it means
A playful way to tell someone to calm down, slow their roll, and stop charging in full-throttle. You use it when someone's getting heated, too hyped, or about to do something rash. It can sound a bit snappy, but a lot of the time it's friendly damage control with a wink.
Usage examples
"I’m about to go off on him in the group chat. Cool your jets, take a breath, and read it again before you hit send."
"Cool your jets, mate, the football transfer window is open until the thirty-first of January, and your favourite striker is not going to sign with the rival club this afternoon while the manager is still in negotiation with the regional director."
"Cool your jets and let me finish reading the email from the holiday agency in Birmingham, the booking confirmation is on the way and the cousin from Manchester has already paid her deposit for the family trip to Tenerife in February next year."
"Cool your jets, man, nobody's stealing your parking spot, they're just reversing."
"Oi, cool your jets, we'll order the food when everyone's actually here."
Where it comes from
Cool your jets emerged in American English of the late nineteen-seventies, coined in the everyday slang of pilots and ground crews at US Air Force bases during the era when supersonic jet engines like the Pratt and Whitney F-100 powered the F-Sixteen Fighting Falcon fighter. The literal cooling of the engines after a sortie was essential before maintenance, and the metaphor for emotional cooling transferred naturally to civilian speech via aviation magazines and television series of the eighties. British English absorbed the phrase through Hollywood films and American sitcom imports of the nineties, and it has retained the breezy military flavour of the original aerospace origin.
