Why the sky is still full of empty 'ghost' flights

In the early days of the pandemic, when demand for air travel abruptly flatlined and international borders closed, "ghost flights" became a common phenomenon. These were empty or near-empty planes traversing the skyline as airline schedules kept to their contractual obligations to fly. The problem is that, nearly two years on, they're still haunting the skies above us. (edition.cnn.com) 更多...