Spacecraft? 1.
Fry: How many atmospheres can the ship withstand?
Professor Hubert Farnsworth: Well, it was built for space travel, so anywhere between zero and one.
In fact, would you get the opposote effect along the sides of the craft, where air is moving fast but parallel to the surface?
A traditional submarine is a huge steel cylinder. I thought there was a good reason for that.
It doesn't have to withstand a pressure, but it does have to contain a pressure. Kind of opposite-ish.
Spacecraft? 1.