Story highlights

Southwest Flight 4013 was headed to Branson, Missouri, airport, but landed at one nearby

Investigators looking at a number of potential reasons for what happened

The airport where the plane landed was not staffed by controllers

CNN  — 

The pilots of a Southwest Airlines jet that landed at the wrong Missouri airport this week were not directed there by air traffic controllers, and should have known they were landing at the wrong location, U.S. Sen. Roy Blunt said on Thursday.

“The federal employees involved did what they were supposed to do. The airline employees involved did not,” the Missouri Republican said in a conference call with reporters.

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Blunt said he had talked with Federal Aviation Administration chief Michael Huerta about the incident. The FAA oversees air traffic control for commercial airline travel.

Southwest Flight 4013 from Chicago’s Midway Airport with 124 passengers was scheduled to land at Branson Airport in southwest Missouri on Sunday night.

Instead, the Boeing 737-700 touched down at Taney County airport - about seven miles away, and with a runway significantly shorter.

The National Transportation Safety Board is looking into the incident as is the FAA. An industry official previously said the FAA had reviewed the matter initially and it appeared there had been no issue with controllers.

The Taney County airport was not staffed by controllers, but they were in touch with air traffic centers along the way.

The two pilots have been placed on paid leave.