Greece has temporarily closed its entire airspace due to communication issues. The Hellenic Civil Aviation Authority said the airspace would remain closed until 4pm. Tourists are being warned to expect widespread delays if travelling to or from Greece.  Greek news outlet Kathimerini reported that a “technical problem” at Athens Flight Information Region was affecting flights in and out of the capital city’s main airport as well as regional flight hubs. Air Live said its analysis of flight trackers showed Greece‘s airspace was largely empty. The outlet said many flights were being diverted to nearby countries such as Italy, Turkey and Cyprus. Arrivals and departures at airports including Athens Eleftherios Venizelos and Thessaloniki were suspended from about 9am local time (7am BST), according to reports. Greek media reported that the problem appeared to be linked to radio frequency systems at Athens and Macedonia Area Control Centres which reportedly went down, knocking out a centre all aircraft entering Greek airspace have to communicate with. Pilots of aircraft already in the air were being forced to land manually …