I was playing on briggs tonight had a base built in a mountain, Very secure hive shielded by structures and a skywall, and somehow someone managed to destroyed it in about 20 seconds. I could hear a reaver but there was no aircraft in sight. It shot through the ground and hit only my hive and that's impossible. So it seems someone managed to clip through the ground with there aircraft ether by glitch or hacking.
Aircraft below ground is a known exploit and it should be very easy for DGC to fix it, all they need to do is put invisible walls around the edges of continents.