US airline Southwest is investigating after a flight bound for Missouri's Branson airport landed safely - at a different airport several kilometres away.

The scheduled flight was carrying 124 customers and a crew of five from Chicago Midway to Branson, Southwest said.

Instead it landed at the Taney County airport, also in Branson.

The runway at Taney County is only about half the length of the one at the intended airport - 1,139 metres compared 2,133 - which could have posed a problem for the Boeing 737.

However with immediate, heavy breaking, the pilot was able to stop the plane about 152 metres before the end of the runway with no injuries, emergency and airport officials said.

Southwest quickly scrambled to the scene "to take care of our customers and their baggage," the airline said.

"We continue to look into the circumstances which led the pilot in command of flight 4013 from Chicago Midway to land ... several miles from the Branson Airport we serve," the airline said.

"We are co-operating with authorities in this investigation."

"We have since reached out to each customer directly to apologise, refund their tickets, and provide future travel credit as a gesture of goodwill for the inconvenience," it pledged.

The mis-directed airplane was expected to leave Taney County today.
A different plane had been brought to the Branson airport to pick up the passengers continuing to the flight's final destination in Dallas yesterday.