Rocket Factory

Overview
The Rocket Factory is needed for building the Hailstorm and Hornet. The building cannot be turned off and is relatively cheap to build. If the player has built as many Hailstorms and Hornets as are currently needed, it is a reasonable building to sell off and build again later when more Hailstorms and Hornets are needed, in case a player is short on population.

Suprisingly, it is not required to unlock the Rocket Truck.