Tlali Tlali, a spokesperson for South African Airways, told NBC Washington that Flight SA 207 originated from Johannesburg and landed at Dulles Wednesday after making a stop in Dakar, Senegal.
Authorities had yet to identify the man, whose body was found by a ground crew about 1:30 p.m. EST, WRC-TV, Washington, reported.
Tlali said the airline regrets "any loss of human life and are deeply concerned about the suspicious circumstances surrounding this incident."
The body was turned over to the Fairfax County Medical Examiner.