He also invented the Skyhook, an air rescue system that involved an airplane and a large helium balloon.

他还发明了高空吊运车，这是一种为飞机和大型的氦气球的空中救援系统。

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He also invented the Skyhook, an air rescue system that involved an airplane and a large helium balloon.

他还发明了高空吊运车，这是一种为飞机和大型的氦气球的空中救援系统。

youdao