Most blueprints I've seen in the real-world often use a sans-serif font, but they're as Tilt described. Wide letters with thin lines (traditionally written by hand). This is a payware font that costs $30, but it's a good example of a blue-print type font. The similar fonts in the sidebar are some other nice examples. You should be able to find something free that's like them on DaFont.

As for the ship itself. I really like the design of the first one. As one already mentioned, it could use airlocks in the corridors. A spaceship, like a real ship — much more like a submarine, really — needs a way to seal off sections that are breached or on fire, else the entire ship is compromised. However, the monochrome and simple design looks much like a company blueprint you'd find in their pamphlets. It has me inspired.