Actually "Farm Gate" was never a "classified" Op, like say "White Star", but their actual combat role was denied for awhile. And you might want to add the good old plain Jane C-47 to the list. Look up the"Dirty Thirty". They were there in the beginning days. And if you count the Mayaguez incident, USAF direct combat in mid May, 1975, involvement ended after that. The final US fatalities due to direct combat with the Communists was there.