They could not provide adequate air cover for ground operations.

他们无法为地面作战行动提供足够的空中掩护。

There goes our air cover.

空中掩护也没戏了。

Has he got air cover?

他有空中掩护吗？

The ships would no longer have air cover from carriers.

风暴舰（暗版航空母舰）生产一种以上的小飞机么？

The ships needed air cover once they reached enemy waters.

已到达敌方的水域，船只就需要空中掩护。