Who decides where planes fly?

The Federal Aviation Administration (FAA) is solely responsible for the control of aircraft operations inside the U.S. National Airspace System. 

FAA Air Traffic Control (ATC) considers several factors through each phase of flight to safely move aircraft from one place to another. These factors include safety requirements, capacity needs, efficiency of aircraft movements and specific noise abatement procedures.

The departure phase of flight starts with a local tower controller. ATC will give the departing aircraft a clearance to taxi to the runway and to take off. The clearance that the tower gives to the pilot is guided by procedures and requirements outlined in the ATC Tower Order. These instructions guide the aircraft during the initial phases of flight and will incorporate any necessary requirements for noise abatement, safety and separation.

The point at which departing aircraft make their turn after takeoff can vary considerably due to factors such as wind, weather, aircraft performance, pilot technique and safety considerations. For example, many of the aircraft that are assigned right turns off of MSP's Runways 30L/R will be heading to northerly or easterly destinations and are utilizing standardized routing to their destination.