The NSRI says the captain and co-pilot of a cargo aircraft, en route from Cape Town to Port Elizabeth, reported the incident.

Spokesperson, Craig Lambinon, says the pilots reported what appeared to be a green object increasing in altitude as it passed the cockpit of their plane.

Lambinon told Algoa FM News the sighting was reported to Air Traffic Control at PE International Airport who requested NSRI's assistance to investigate the possibility that an aircraft or craft may be in difficulty.

AlgoaFM