Yes, during the Korean War Soviets sent Mig fighters into Korea, piloted by Soviet pilots. They engaged with American fighters, some close engagements allowed American pilots to physically see what were clearly Russian pilots fighting them. America air force were also able to correlate the action/skills of pilots opposing them with rotation schedules of Soviet combat wings in the far east.

During the Vietnam War, Soviet "trainers" and "technicians" operated surface-to-air missile sites, particularly during the middle to late 1960s, before North Vietnamese soldiers were trained on the equipment.