Reportedly, Viljoen crashed the plane in attempt to kill his wife.
Charl Viljoen, a pilot with Kalahari Air Services, is said to have stormed out of the club house where his wife was attending a baby shower before stealing a small aircraft.
The Matsieng flying club in Botswana said the pilot had been an "uninvited guest" at the function in its aerodrome.
A statement read: "It is rumoured that the pilot was involved in a domestic dispute earlier in the afternoon". It said members had "sensed that the pilot might have had an ulterior motive" and "ordered an immediate evacuation of the club".
"The final, extremely low-level run by the aircraft along runway 36 resulted in an impact with the Matsieng Flying Club facility at ground level".
Viljoen was the only fatality and there were no injuries, however, 13 vehicles, a control tower and the clubhouse were all destroyed.
Warning: Video contains scenes of a plane crash and graphic language.
A witness claims that the man, who is a pilot, stole an aircraft before calling a friend who was at the baby shower and asking where his wife was.
Viljoen had been working as a chartered pilot in Botswana since October 1, 2018.
He then made a decision to crash the plane into a building where the wife was attending a baby shower.
"He phoned his one mate on the ground there who was still at the party and he wanted to know where his wife was", the man told the news outlet. He was pronounced dead at a local hospital. Then the plane crashed into it.
The police and Botswana aviation officials were investigating the incident.