Net turret (anti-air) (Air sweeper alternate)

It can be an alternate form of air sweeper where it can take affect air troops in an interval.

Troops affected by the air current are temporarily grounded (loses the ability to fly but is still able to move and fight).

Interval and range can be the same as air sweeper.

To be honest, I think we have enough defences to deal with the air attacks. Adding any more will just ruin any air attacks and would make people never use the troops because of the attack's difficulty.