A Vietjet Air Airbus A320-200, registration VN-A692 performing flight VJ-8861 from Hanoi to Dalat (Vietnam) with nearly 200 passengers, departed Hanoi at about 17:10L (scheduled departure from gate at 15:45L) transponding callsign VJC8575 and landed at Nha Trang's Cam Ranh Airport (Vietnam), about 55nm northeast of Dalat, at about 19:00L (12:00Z) following what appeared to be an uneventful flight.
Passengers reported they were astonished as they could not recognize the airport as their home airport after landing until they discovered they were put down about 140km from their home town. No announcements had been made by the crew, that the aircraft was being diverted.
In the meantime Vietjet's flight VJ-8575 (callsign VJC8575) from Hanoi to Nha Trang with scheduled departure at 16:35L did not depart from Hanoi despite past scheduled departure time, the nearly 200 passengers were waiting for departure in the departure lounge.
Vietnam's Authorities opened an investigation into what appears to be a serious error and required Vietjet to explain the occurrence assuming flights 8861 and 8575 were confused on the ground, the similiar number of passengers contributing to the error.
Vietjet reported that the crew did not deem the weather at Dalat suitable for landing and therefore diverted to Cam Ranh Airport.
Following landing at Cam Ranh Airport VN-A692 flew to Dalat delivering the passengers to their destination, picking up the passengers waiting for the return flight VJ-8862 and returned to Hanoi now correctly transponding callsign VJC8862