Ok so a while ago I suggested gates. Nobody responded. Today I stumbled upon a thing about hanger doors. So new idea.
A hanger door multiblock. Different max sizes requiring different advancements. Maybe a option for a expensive shielded version. Basically you right click the sign, and the blocks start moving up, sideways, or down. You do need space in said direction to be able to place it and you can specify what way sorta like a turret. Some sort of wiring would be required for controls or be mounted on the wall right by the hanger. Basically a way to let some ships in and out, and others to stop from exiting (unless they use enough force). Maybe smaller versions to just lock up a base like on Endor in episode 6 / 3. Basically, right click sign, and bam door starts to retreat or close (it would take more or less time depending on size but probably like 1 block line per second or 2). Blocks for door could be iron blocks (hopefully not), iron bars, stone brick, or some other block.