Two project directors were killed when a light aircraft registered in South Africa crashed in Tanzania on Saturday, the company said on Sunday.
"U Dream Global: Cape to Cairo Challenge is devastated to report that there has been an accident of the flight support aircraft and that the Project Directors, Des Werner and Werner Froneman, have lost their lives," a short statement on their Facebook page said.
"No one else was involved in the accident. We kindly request everybody's understanding at this incredibly difficult time.
"Our love and thoughts go to Des and Werner's friends and families."
U Dream Global is a programme founded by Megan Werner, the daughter of Des Werner, to promote and facilitate innovation among young people.
Their vision was to build and fly a plane from Cape to Cairo.
Condolences were pouring in after the statement was posted.
On July 8, the team of teens landed safely in Cairo.
Spokesperson for the Department of International Relations and Cooperation Clayson Manyela confirmed the tragedy.
James Pitman of The Aircraft Company, which is the developer and manufacturer of the Sling aircraft which crashed, said the plane that crashed was a different Sling to the one used by the students in the U Dream project that flew to Cairo.