We’ve had foreign exchange officers and NCOs since at least the late 70s.
Nearly $100 million last year went to over 143 countries under the IMET (International Military Education and Training) portion of the Security Assistance budget. This is above and beyond the personnel exchange programs, so there are literally thousands of foreign military, normally with their families, in the US at any one time.
We’ve had foreign exchange officers and NCOs since at least the late 70s.
1805.
One of the guys I went to college with ended up as an Instructor Pilot in the mid-70s teaching Iranians to fly.
Had to learn to speak Farsi to have any chance.