Air defence has ceased to be an issue of concern only in conventional warfare scenarios, a leading South African defence analyst has warned. "In Africa, clandestine airlift is common," Helmoed Heitman told the 2013 South African Joint Air Defence Symposium in Pretoria on Tuesday.

These clandestine air transport activities are not just undertaken by governments. They include illegal activities by smugglers and rebel groups. "Even mineral ores are flown out of the DRC [Democratic Republic of Congo], by smugglers and by rebels."

"We need to understand that narcotics are moving into Africa," he pointed out. "Narcotics also move by air, including by dedicated smuggling flights. We are going to see a lot more of this."

A fundamental requirement of air defence systems is to be able to detect, identify and track potential targets, before any weapons are fired. The detection, tracking and classification capabilities of these systems are thus of great value in monitoring and helping deal with airborne criminal activities, even if no weapons are ever fired.

But real military operations do exist. South African forces have been, and are, involved in such operations in other parts of Africa. Currently, South African troops form part of the United Nations Intervention Brigade in the DRC, opposing rebel forces. Here, too, air defence can have a role to play. "Irregular forces can use aircraft for combat," noted Heitman, citing the case of the Air Tigers during the Sri Lankan civil war. Rebels in the DRC use aircraft for transport operations. And transport aircraft have been used as bombers, with bombs rolled off tail ramps or through cargo doors. The Sudanese Air Force has done this quite a lot.

"There are also UAVs [unmanned air vehicles]," he warned. "There is nothing to say that irregular troops won't use them." On the other hand, DRC rebels were known to have their own anti-aircraft guns.

"Anybody who is operating in Africa is going to make use of the air at some point," affirmed Heitman. This applied whether they were regular armed forces, guerrillas or criminals.