Your seat cushion can be used as a flotation device.

你的椅垫可以拿来当作浮具使用。

In case of a water landing, you may be used as a flotation device.

当水上登陆的时候，你也许应该使用漂浮设备。

They'd assigned me a "swim angel" with a flotation device in case I had trouble, but I left her behind.

他们给我分配了一个“游泳天使”，准备了救生设备以防我遇到麻烦，但我把她甩在了身后。

In the unlikely event of an emergency water landing, you may find a flotation device beneath your seat cushion.

如果发生水上迫降的紧急状况，你可以在座位下方找到一套漂浮设备。

If you can't swim well but you need to cross a large body of water, you can use your pants as a flotation device.

如果你游泳不好，但你需要游过一大片水域，你可以用裤子作为漂浮。