What happened to the plane?
The aircraft may have crashed into the Andaman Sea. It is monsoon season in Myanmar but there were no reports of stormy weather in the area at the time the plane went missing.
Nine navy ships and three air force planes were dispatched to search for the aircraft, which disappeared as it flew from the southern city of Myeik to Yangon.
Sources told AFP that debris had been found in the sea off the coastal town of Dawei, which lies an hour's flight south-east of Yangon.
The commander-in-chief's office said the plane lost contact with air traffic control at 1:35 pm (12:25 pm IST) yesterday, about half an hour after takeoff.
Who were the passengers?
A spokesman from the military's information team said two-thirds of passengers on board were women and children.
More than half of the passengers were from military families, including 15 children, along with 35 soldiers and 14 crew members, the army chief's office said in a statement.
"Some were on their way for medical checkups and to attend school," said a spokesman from the military's information team.
There was conflicting information on the number of people on board, but in the latest update, the military said the plane was carrying a total of 122 people.
Where was the plane found?
An air force source confirmed to AFP that a Navy search and rescue ship had found debris in the Andaman Sea that is an hour's flight south of Yangon, Myanmar's commercial capital.
"Myanmar military has found pieces of the damaged plane in the sea 136 miles (218 km) away from Dawei city," said Naing Lin Zaw, a tourism official in Myeik, citing the military and adding that they were still searching the sea.
For rescue, several navy ships and air force planes were sent to search for the aircraft, which was flying at an altitude of more than 5,486 metres.
Which plane was it?
The plane was a Y-8F-200 four-engine turboprop, a Chinese-made model still commonly used by Myanmar's military for transporting cargo.
The former military junta bought many of the aircraft from Myanmar's giant neighbour during their 50-years of isolated rule, when they were squeezed by Western sanctions.
A former executive at the aviation ministry said many of the aircraft in Myanmar's fleet were old and decrepit.
"Myanmar air force has (a) very bad safety performance," he told AFP, asking to remain nameless.
However, the army said the missing plane was delivered in March last year and had logged 809 flying hours.
The military named the captain of the plane as Lieutenant Colonel Nyein Chan, who it said had more than 3,000 hours of flying experience.
Myanmar's military fleet has a chequered recent history of plane crashes
A five-strong crew died when an air force plane burst into flames soon after taking off from the capital Naypyidaw in February last year.
Three army officers were also killed in June when their Mi-2 helicopter crashed into a hillside and burst into flames in south-central Bago.
Commercial jets have also suffered frequent incidents
The worst in recent years was in 2012 when an Air Bagan jet crash-landed in thick fog and burst into flames short of the runway at Heho airport, killing one passenger and a motorcyclist on the ground.
A surge in demand for air travel as Myanmar opens up has stretched the impoverished country's aviation infrastructure, in particular in remote airports.