Currently the macroblocks only have placement options for normal placement and free off grid placement. Its really frustrating having to manually remove structures every time I place down a macroblock, and air mode would reduce that frustration immensely. It's also frustrating when I want to build on grid, but something on the map is blocking the placement. It's a lot of work to try and align a placement in free mode, so a macroblock ghost mode would make building much faster.