When Azerbaijan threatened  in 2011 to shoot down flights to the newly built airport in Nagorno Karabakh, swift international condemnation  forced them to back down. Now, with the long-delayed airport apparently close to opening, Baku has reiterated those threats. Reports News.az :
Azerbaijan’s Missile Defense Forces are keeping under control the entire airspace, including the occupied regions, a senior official of the Military Air Forces and Missile Defense Forces told APA exclusively on condition of anonymity.
He said the airspace is kept under control through the radar systems. Azerbaijani Army has been placed on alert in order to prevent any attempt of the opposite side.
“We record even the drones launched by Armenians in Karabakh airspace. Armenians’ attempts to operate unpermitted flights in this territory will be prevented. We are keeping under control all the processes and ready to prevent them. It is possible through various methods, the opposite side knows it very well,” he said.
The Armenian authorities who control the disputed territory of Karabakh hope that the establishment of flights in and out of the self-proclaimed republic will help mitigate their isolation; it's now only possible to reach the territory by a long drive through the mountains from Armenia.
The language from this unnamed official is a bit more guarded than the last time, when Azerbaijani officials used words  like "destroy" and "annihilate" in reference to flights to Karabakh. And probably more importantly, it wasn't made publicly, so there hasn't been the same sort of reaction internationally. But the message is obviously the same. And the threat still seems just as empty: although the U.S. ambassador to Baku recently reiterated  that the opening of the airport would be "not helpful," shooting down a civilian flight, it should go without saying, would be catastrophic for Baku's international position and whatever intimidation it would accomplish against Armenia would be vastly outweighed by its becoming an international pariah. So it's not clear what they're trying to accomplish with even these sorts of veiled threats.