AirAsia Indonesia flight QZ8501 has lost contact with air traffic control.
In a statement on its Facebook page, AirAsia says the flight from Surabaya to Singapore lost contact at 07:24 Singapore time.
The aircraft was an Airbus A320, registered PK-AXC.
AirAsia says that search and rescue operations are underway and that the airline is cooperating with the relevant authorities.
Around 162 passengers and crew members are believed to be on-board the plane.
QZ8501 is the second aircraft to be reported missing this year, following the mysterious disappearance of Malaysia Airlines flight MH370 in March.