About a dozen of our pilots worked two years for a major European airline, following a very creative agreement, as "Cruise pilots", when they and many others were laid off here in the early 90's.
One of the pilots who worked there was on our jumpseat in the early or mid-90's to ABQ, a western US city. He described firsthand a flight over Russia long after midnight while he was in the 744 Captain's seat. Straight ahead he saw the lights of another plane, and it was at the same altitude! I seem to remember that "Kreijde" (his nickname) was beginning to level off at a higher altitude, and so he smoothly but quickly pushed the nose over and missed the other plane by less than three or four hundred feet or so. After he asked ATC about other aircraft, no others were said to be in the area at that altitude.
I can't remember if the airline already had TCAS onboard.