The light aircraft in which the pair was flying plunged into a remote field about 3km from Birr just before 5pm.
Both the gardai and the Air Accident Investigation Unit were today investigating the cause of the crash.
The pair were today described as "flying fanatics" who regularly flew together in Co Offaly.
A member of the public is understood to have called the emergency services and the aircraft was discovered upside down in a marshy field.
Niall Doherty had recently qualified as a flying instructor and Damien Deegan was one of his students.
Friends of Mr Doherty, who is from Roscrea, Co Tipperary, today revealed that he had recently split from his long-term partner to whom he was engaged.
"Niall was going through a tough time as his engagement was recently called off but in recent days he appeared to be getting over the pain of it. It makes it even more tragic," a friend told the Herald.
Mr Doherty was one of four children and was involved in running the family's DIY store in Roscrea.
Meanwhile, in Offaly, local representatives today said the tragedy had left the community "numb with shock".
Cathaoirleach of Birr Town Council Michael Loughnane, who knew the Deegan family, said they were "inconsolable".
"They are a very respectable family and are obviously inconsolable at what has occurred. Damien was an avid flyer and just loved being in the air. He died doing what he loved," he told the Herald.
Damien was very involved in GAA in the community and he was the vice chairman of the handball club.
"We are just devastated by this tragedy," said local Birr councillor John Carroll.
"Damien was very active in the community and the airfield was part of the village since it was formed in the 1960s."
Damien was one of the most committed lads in the community, said Fr Michael Reddan of St Brendan's parish in Birr.
"He was very caring, always fundraising. He was very conscious of doing good for others. He was an exceptional young man."
He used to work in Tesco supermarket in the town and it is reported that he had two brothers and two sisters.
Inaccessible terrain hampered search and rescue efforts and the garda helicopter was deployed. A search and rescue helicopter was also involved. Their bodies remained in the wreckage last night due to fears over hazardous aviation fuel while investigators from the Air Accident Investigation Unit of the Department of Transport tried to determine the cause of the crash.