Traffic patterns standardize the flow of traffic in and out of airports, in order to provide to a more orderly flow of traffic and aid in pilot situational awareness. The standard traffic pattern is 1,000 feet above the airport elevation for piston aircraft, and 1,500 feet above the airport elevation for turbine aircraft. In a standard traffic pattern, all turns are made to the left. It contains five legs, which are:

  • Upwind: This leg of the traffic pattern is aligned with the departure course from the runway being used. Since takeoffs and landings are made into the wind, this leg is logically referred to as the upwind leg, since the airplane is flown into the wind.
  • Crosswind: The next leg of the traffic pattern extends at a 90 degree angle away from the upwind leg. In a standard pattern, the pilot would make a left turn from the upwind leg and fly with the wind now coming from the right.
  • Downwind: From the crosswind leg, the pilot makes another left turn and flies downwind. The downwind leg is parallel to the runway being used.
  • Base: The base leg is perpendicular to the landing runway. In a standard pattern, the pilot makes a left turn from the downwind leg, placing the wind now off the left side of the airplane.
  • Final: On the final, the airplane is aligned with the arrival runway, facing into the wind.

Nonstandard traffic patterns are sometimes created for obstructions or noise abatement. In a non-standard pattern, turns are made to the right instead of the left. Additionally, traffic pattern altitudes may be altered to suit specific conditions at a particular airport.

At controlled airports, the tower may assign left or right traffic, or instruct the airplane to enter a specific leg of the traffic pattern. For example, the tower might instruct and aircraft to "enter the right downwind for runway 13, report midfield on the downwind" or "enter left base runway 18".

At uncontrolled airports, standard pattern entries involve entering the downwind leg at a 45 degree angle at traffic pattern altitude. This is the recommended method of traffic pattern entry. Alternatively, pilots often fly directly over the airport at pattern altitude, crossing over at mid-field to join the downwind leg of the traffic pattern.

ยง 91.126 Operating on or in the vicinity of an airport in Class G airspace.