Aeroplanecargo faces even tighter restrictions on shape and size, not to mention the need for runways.
飞机货运对形状和大小有更加严格的限制，更不必说对跑道的依赖。
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In February 2016, the US National Transportation Safety Board issued a warning about lithium batteries in aeroplanecargo, describing them as "a fire and explosion ignition source".