During the five years of civil war in Kachin region, while Burma Air Force keep dispatching its MIGs and attack helicopters to the KIA outposts which sit along Sino-Burma border, I kept wondering how were they able to fly along international boundary without entering into Chinese airspace?
China is currently fighting tooth and nail over maritime disputes of Senkaku, Spratly, Scarborough Shoal, and Paracel islands, which are hundreds of miles away from the shores of Mainland China. President Xi repeatedly claims in international forums that it would allow no nation to compromise its territorial integrity. Reality differs in Kachin war, Burmese Tatmadaw which has been attacking Kachin forces (KIA) are repeatedly using sovereign Chinese airspace of Yunnan Province, on its Mainland, to maneuver its flights.
Unless Tatmadaw obtained an approval from China, it is unimaginable what the consequences of such incursion would be. If similar event were to happen somewhere in South China sea, events like Crimea would have easily erupted. Question now for Burmese public is, what did the Govt of Burma and Tatmadaw give in return for using Chinese airspace?