A Swiss court has found four employees of an air traffic control firm guilty of manslaughter over the deaths of 71 people in a mid-air collision in 2002.
The Russian children on board were going on holiday to Spain
Three of the four managers convicted were given suspended prison terms and the fourth was ordered to pay a fine.
Another four employees of the Skyguide firm were cleared of any wrongdoing.
Prosecutors had said a "culture of negligence" at the firm contributed to the mid-air collision, which killed mostly Russian children.
The charter aircraft carrying Russian children to a holiday in Spain collided with a cargo plane in Swiss airspace on 1 July 2002. The wreckage came down in Germany.
All eight men on trial had maintained their innocence. Seven had continued working for Skyguide until the time of the verdict.
The BBC's Imogen Foulkes, in Berne, says it is significant that the four Skyguide employees acquitted were all air traffic controllers - rather than managers.
She says this shows the judges backed the prosecution's view that the managers at Skyguide were responsible for introducing negligent, potentially dangerous working practices.
Two separate investigations have already found what were described as organisational deficiencies within Skyguide. These deficiencies were said to have contributed to the accident.
The trial revealed that minutes before the crash a single air traffic controller was in charge of 15 planes: He made 118 radio contacts with them, and he was guiding a plane into land.
Technical repairs were being carried out and some radar systems were not working.
The air traffic controller in question was later stabbed and killed by the father of two of the children who died.
At the time, Skyguide insisted that having just one air traffic controller on duty was normal - but it has since outlawed the practice, and provided financial compensation to some of the bereaved families.