Milwaukee’s General Mitchell Airport Sees Busiest Month in History CheapOair Staff September 20, 2010 general General Mitchell Airport sees busiest month in July General Mitchell Airport in Milwaukee reported its busiest month ever in July. It’s the most recent in a string of 11 months of consistent passenger growth at the airport, which has benefited from a turf battle among low-cost carriers AirTran, Southwest and Frontier, which gained the airline previously known as Midwest. The airport says it served 928,497 passengers for the month, an increase of 136,876 from July 2009. Its previous one-month high of 922,984 passengers came in June. Source: USA TODAY