"Montblack" wrote in message
...

How did they plot all of those planes' positions? Pilot reports or their
own triangulations?


Position reports and filed speeds were used to plot positions of aircraft on
a large map table initially. Eventually the map table was dispensed with
and controllers just used the "map" in their heads.



With no radar, what were the controllers doing in the late 30's, waiting
for pilots to call in and tell Center where they thought they were?


Not pilots, Center controllers didn't have direct pilot/controller radio
communications until the early fifties. Position reports and clearances
were relayed via telephone through Airway Radio Stations (Renamed Airway
Communication Stations in 1938, Air Traffic Communications Stations in 1958,
and Flight Service Stations in 1960. That's why we address FSS as "Radio".)
and airline dispatchers.