At the peak of Greece’s annual summer tourist rush, green icons marking commercial jets packed with holidaymakers stack up across the radar screens of Athens air traffic controllers, creating a high-stakes logistical puzzle that tests even the most experienced professionals. “Look at this sky, it’s crazy, there’s no room for any more planes!” said Olga Toki, vice-president of the Association of Air Traffic Controllers of Greece, summing up the unprecedented pressure facing Greece’s overstretched aviation workforce this summer.