Image copyright NTSB Image caption The flight landed about six miles prematurely

Federal investigators are blaming pilot error for causing a Delta Air Lines flight carrying 129 people to land at the wrong airport in South Dakota.

The flight from Minneapolis landed at the Ellsworth Air Force Base, about six miles (10km) from Rapid City.

The US National Transportation Safety Board blamed Delta's two pilots for not using all the instruments at their disposal to determine their location.

The plane was held for more than two hours before it could take off again.

The incident happened last July but the NTSB report into it was released on Tuesday.

According to officials, the two airports have runways that face the same direction - from northwest to southeast - which likely contributed to the error.

The two Delta pilots had been suspended pending the inquiry.

Delta "offered a gesture of apology for the inconvenience" to the passengers involved.

A similar incident occurred in 2004 when another passenger plane landed at Ellsworth Air Force Base.

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