Only one person survived when the Antonov AN-26 transport aircraft with 20 air force cadets and seven crew members on board crashed and burst into flames on September 25.

Ukraine's President Volodymyr Zelensky attended the ceremony on Kharkiv's central square where coffins were set on pedestals alongside portraits of the victims.

Relatives of the cadets and crew wept and hugged each other while sombre music played, an AFP journalist on the scene reported.

Following a minute of silence, three military planes flew over the square.

Ukrainian Defence Minister Andriy Taran said the crash was a "black page" in Ukraine's history and described the victims as "young, promising guys" who died too young.

"All of Ukraine is mourning with the families," he said.

The transport plane crashed during landing near a highway around two kilometres (more than one mile) from the Chuguiv military air base.

Most cadets on board were aged between 19 and 22.

Investigators are probing several possible causes including technical malfunction, human error and poor maintenance.