In gratitude to the many readers who have sent in pointers to this item, and in ongoing appreciation of the living national treasure that is Randall Munroe of xkcd, and as a little pre-Superbowl feature, here is a look at Munroe's latest "What If?" feature. In this installment, "Interplanetary Cessna," he asks how a small aircraft would fare on different bodies in and around the solar system. Sample visual aid:


Sample explanations, based on flight-simulator experiments:
The Sun: This works about as well as you'd imagine. If the plane is released close enough to the Sun to feel its atmosphere at all, it's vaporized in less than a second....

Jupiter: Our Cessna can't fly on Jupiter; the gravity is just too strong.... Starting from a friendly sea-level pressure, we'd accelerate through the tumbling winds into a 275 m/s (600 mph) downward glide deeper and deeper through the layers of ammonia ice and water ice until we and the aircraft were crushed. There's no surface to hit; Jupiter transitions smoothly from gas to solid as you sink deeper and deeper....

Uranus: Uranus is a strange, uniform bluish orb. There are high winds and it's bitterly cold. It's the friendliest of the gas giants to our Cessna, and you could probably fly for a little while. But given that it seems to be an almost completely featureless planet, why would you want to?

Neptune: If you're going to fly around one of the ice giants, Neptune (Motto: "The Slightly Bluer One") is probably a better choice than Uranus. It at least has some clouds to look at before you freeze to death or break apart from the turbulence.
And so on. As the illustration above suggests, in all cases you'd prefer to be doing your flying in a Cirrus, complete with parachute.

(And, yes, I know -- except that in most of these places the atmosphere is too thin for the parachute to do any good. Still. Congrats and thanks to Munroe and his readers.)