Pan Am(PA), DL and the Americans forces put down the foundation of FRA into what it is today. Before WWII Berlin was the hub for LH, but with the division of Germany and Berlin LH was not allowed to operate out of Berlin. AF, BA and PA dominated western traffic in and out of Berlin (PA operated 650 flights out of TXL a week) and PA built its intercont operations in FRA with TATL flights continuing on to the Middle East and India, onwards to the Far East.

After the cold war and imminent demise PA cashed out sold its pacific operations to UA and the TATL to DL. LH took over their German operations and some of the intercont routes.

Given the convienient location and existing infrastructure, FRA beat the Berlin airports and MUC/DUS in the post cold war growth. MUC could have given FRA a run for its money if the move from Riem to its current site was not delayed by 10 years due to local resistance.

SXF with its SU and IF operations was never a candidate as it was tiny.