President Trump is ripping air traffic controllers a new a**hole as the government shutdown drags on … threatening to dock the pay of those playing hooky from their posts.

Trump fired off the financial threat Monday morning on his Truth Social app, claiming any air traffic controller who doesn’t work during the shutdown “will be substantially ‘docked.'”

The messaging comes in the wake of the FAA ordering reduced air traffic at 40 major airports across the country … tons of flights are canceled or delayed, and travelers and pilots are feeling the stress … especially as the holiday travel season ramps up.

But for those who called out sick or otherwise didn’t show up to work, Trump says … “I am NOT HAPPY WITH YOU.”

Trump adds … “You will have a negative mark, at least in my mind, against your record. If you want to leave service in the near future, please do not hesitate to do so, with NO payment or severance of any kind!”

Federal workers, including air traffic controllers, aren’t being paid during the shutdown … but once the government is reopened and funded, those workers are expected to get back pay.

Still, there’s been tons of stories about air traffic controllers taking side jobs — like food delivery — to make ends meet … and a national shortage of air-traffic controllers was already an issue before the shutdown.