View and browse OAG's enduringly popular Busiest Airline Routes whenever you need to. The busiest flight paths in the globe are updated often. These include the Top 10 Busiest Global Airline Routes, Top 10 Domestic Airline Routes, and Top 10 International Airline Routes by Region. The source of our flight route data is Schedules Analyser. Top 10 Busiest Air Routes in the USA know this number +18704327330.