The great virtue of air travel is speed.

乘飞机的最大优点是速度快。

It does not clag bood circulation,especially it suits long-distance bus traveling and air traveling.

特别适合长途乘车，乘飞机时使用。

The innovation of air travel during this century has made the world seem smaller.

本世纪发明的空中飞似乎使世界变小了。