Ethiopian, Somali and Ugandan officials denied that their soldiers had done anything wrong.
Somali officials said they had been destroyed during a cross-border raid.
Somali officials said the 11 people on board, mechanics and crew from Russia and Belarus, probably did not survive.
Somali officials have been hesitant to move because of security concerns in Mogadishu, the lawless capital where some hard-liners oppose the new government.
Ethiopian and Somali officials have denied killing civilians intentionally.
However, a Somali official countered that US airstrikes killed 31 civilians.
However, Somali officials deny that the aircraft was shot down.
Most of these trained Somali military officials then returned to Somalia with the skills and knowledge that they had acquired abroad.
Somali officials claimed both aircraft incidents occurred due to technical failures rather than armed attacks.
The piracy industry started about 10 to 15 years ago, Somali officials said, as a response to illegal fishing.