Airlines restrict the use of laptops on aircraft during take off and landing in case of interference with the navigation systems. But there are other dangers. According to Aviation Week & Space Technology magazine, the number of in-flight injuries caused each year by turbulence may be grossly under-reported. While the FAA only recorded 80 serious and 769 minor injuries over a 16-year period, flight attendants and other sources said that some major US carriers have experienced 200 to 300 injuries in a single year. And one of the reported sources of injury during turbulence upsets are laptop computers, that can become flying bricks” in the passenger cabin, says the report.