User blog comment:Warwolf 51/The Random War Room/@comment-7178845-20140203025152/@comment-11135771-20140203030713

Make the ship first, leave the base (one block only) hovering a bit below it. When you're done the ship, lower the base to how far you want it to be. Then keep adding large blocks to the bas and checking the info panel until it goes from high draft, low height to high height, low draft. When that occurs, remove a few blocks until you find the exact middle point (play around with various types of blocks until you find it, this is a very precise point) which will cause the height and draft to be more or less equal (doesn't have to be really equal, the goal is pretty much to just get it so that the base is submerged and the ship is airborne). Go into test run, the ship should be in the air by at least 200m or so without the base showing, and at neutral throttle should slowly fall. Add propellers to the back of the base and then some pushing upwards, and test run again. This time the same thing should happen, but at full throttle the ship should go slowly upwards and also move forward. Speed isn't a huge issue; large flying ships usually go between 2 knots at the lowest all the way to 30 knots for fast ships like Peregrine and Trident, although weird designs like the Locusts can go even faster (IIRC the Locust swarm moves at around 70 knots).