At Chivenor and Brawdy the 'flag' was positioned on the downwind side of the runway with the cable laid out in an 'S' loop. The tow a/c (Hunter/Meteor) then positioned alongside on the upwind side for the hook up. I don't recall the tow aircraft ever being airborne before the flag started moving so there was always an element of dragging the flag on its spreader bar washers.
Dropping was as described above but on the command of the Local controller in ATC