Planters Flying Tweaks

Meant to be use in combination with Flying Forts (https://steamcommunity.com/sharedfiles/filedetails/?id=1835113084). Replaces balloons and antigravity devices with smart balloons and smart antigravity devices. These "smart" devices have the same base lift as the normal versions, but will try to adjust lift up / down if your fort is accelerating in one direction to help keep you in the air. This mod lets you use all the same designs as flying forts - it just makes it a bit easier to keep your forts in the sky. It also makes the following minor tweaks: 1. Increased placement angle of balloons, antigravity devices, and weights. 2. Enables placement + deletion of explosive barrels. 3. Reduces build time of propellers and jets.