For the week of the EAA event the Oshkosh Airport is the busiest airport in the world handling on an average day about 3,000 operations in 10 hours. The controllers who work that week are chosen like umpires for the World Series. The FAA picks 50 of the best from various facilities and sends them to Oshkosh.
When I started with the FAA I was at St. Pete/Clearwater Airport Tower in the 1970s's. That airport is on the edge of Tampa Bay nine miles west of Tampa Int'l Airport. It's was a very busy civilian airport of light aircraft and executive jets and Coast Guard Air Station and back in the 1970's when fuel was cheap we handled about 250,000 operations per year. I once tried to get to Oshkosk for that week, but they only selected from their region, the Great Lakes and I was in the Southeast Region.
At St. Pete/Clearwater in what we called our 'calm wind' setup, we operated traffic on all 3 intersecting runways at the same time. Oshkosk is able to run so many more operations because they have special procedures setup in advance and pilots are aware and the flow is almost automated. In the southeast corner of St. Pete/Clearwater airport you can see Airco Golf Course in the photo below. It opened in 1962 and is where I learned how to play golf. Unfortunately it was closed in 2011 because it was losing money for the county.
When I was in the Army I worked for a year at Hunter AAF in Savannah, Georgia. We had about 350 based Hueys and 700 Vientamese student pilots and our operations were over 2,000 a day, which was actually busier than O'Hare. We also had special procedures that the pilots all adhered to and were able to keep the traffic moving and separated by different altitudes inbound and outbound.
When the Vietnam War started winding down in late 1972 the Hueys were moved out. From the photo you can see a large ramp, it was actually very big. We once had twenty C-141's parked on that ramp at one time, the runway is 12,000 feet long (over 2 miles). At the far western end south of the runway was the Cobra AH-1 school. Army pilots transitioning into Cobra helicopters came there for a months worth of training.