Uranus is such a depressing planet that the inhabitants will do just about anything to take their minds off the neighbourhood–such as flying about in turbojet aircraft that are basically dirty big engines that you sit inside. Looking port and starboard is easy enough, but seeing straight ahead (as in where you're going) is a bit of a pain.
According to the article accompanying this painting, the Uranian aircraft fly at 500 mph in the atmosphere and 150 mph underwater (don't ask), are 15 ft in diameter and 80 ft long, and weigh in at 100,000 tons.
The implications of such technology is so... TONS?!?!?