Indonesian Transportation Ministry spokesperson Adita Irawati said the Boeing 737-500 took off from Jakarta at about 1:56 p.m. and lost contact with the control tower at 2:40 p.m.
A statement released by the airline said the plane was on an estimated 90-minute flight from Jakarta to Pontianak, the capital of West Kalimantan province on Indonesia's Borneo island. There were 56 passengers and six crew members onboard.
Irawati said in a statement that a search and rescue operation was underway in coordination with the National Search and Rescue Agency and the National Transportation Safety Committee.
Local media reports said fishermen spotted metal objects believed to be parts of a plane on Saturday afternoon in the Thousand Islands, a chain of islands north of Jakarta.