If one could fly like Superman, how hard would it be to navigate the planet?

Yes similar to what the last poster said, the difficulty would change the more practice you got. Kind of like learning to explore your neighborhood on a bike when you were a kid: all of a sudden you have the ability to travel further and faster than you could by walking, but you still rely on what you can see and remember to find your way around once your house is out of sight.

You start to remember landmarks whenever you go south (or turn right from the front of the house), then another beyond that, and so on. You never really develop a square map-like picture of where you are and where everything is, but more like a tree branch shaped image of what’s to be found along various paths and forks from them radiating out from home.

I’ve watched a few videos made by paragliders… one guy likes taking off from an urban area and flying to nearby fast food places to pick up an order. Although he brings his phone he doesn’t use it for navigation. He knows that the place he’s going is say 5 miles away over that particular hill, and once he’s up in the air and getting near he can recognize the street patterns and building shapes & colours to spot the place. Of course that all relies on his having been there before or seen what it looks like from aerial maps.

I think navigating the planet (as in flying really far really fast to somewhere you’ve not been before) would be a lot harder to do than slowly exploring locally and gradually building your knowledge of what’s to be found where. I actually find navigating long (hundreds of miles) distance on Google Earth rather hard with all the layers and measurements turned off. Try clicking and dragging the map to get from one place to another… when it’s zoomed in close enough to follow roads or rivers, I lose track of how far I’ve gone. Since there are dozens and dozens of intersections or river bends between point A and B, they tend to start blurring into each other and I need to zoom out to see where I’ve scrolled to. If I am zoomed far enough out to have an idea how far I’m dragging the map, I usually can’t see enough detail on the landscape to recognize the target location I’m looking for. I quickly fly over to the general area my target is in, then zoom in and scan around for recognizable features. More often than not either scrolled in or zoomed out I get frustrated and turn some labels on to find the place.

Actually, with a Mercator Projection map and a compass at the point of origin, one could go anywhere (at least between 70° North and South) simply by going in a straight line. Knowing where to stop might be a problem if one’s target was too small. (I am only relatively sure about the 70°–I know that at the poles Mercator is useless and I think that that was the latitude where it breaks down.)
That is how the Mercator Projection works and why, despite its distortion of many areas on the globe, it has been used by mariners for centuries. One simply plots a course from where one is to where one wishes to go, marks the path with a straightedge, and follows that compass heading.

Of course, weather and oxygen would also be issues depending on where one wished to go.

Yes, well, that pretty much describes me before climbing into an ultralight or Cessna or Piper for a trip… then I’d have not just the map but any notations I thought would be useful on a clipboard strapped to one leg before I took off. It’s sort of how we mere mortals do that navigation thing with no superpowers and limited technology.

Yep, pretty much. I recall some days when it would be 90 F on the ground and we’d be wearing winter gear for a planned ascent to 9000 or 10,000 feet. You could probably strap on a backpack and use that to stow the gear when you arrive at your destination.

Yep. Except my landings are acceptable. (Ralph, being invulnerable, never really had a need to upgrade from “stop flying by colliding with the scenery” method of “landing”).

Based on my own flying with minimal aircraft, you do learn to recognize landmarks from the air, and interstates can make pretty good route markers once you learn to recognize them from the air.

I wouldn’t necessarily avoid snow/cold regions but I would bundle up extremely well. Mountains have their own hazards, with air currents that can be extremely hazardous. We still haven’t had a firm number of how fast we can fly, or how vulnerable we’d be to something like turbulence.

I’d avoid significant weather of any sort, regardless of temperature.

I’d probably plan a trip as a series of short hops until I really got to know a route well. Also, I presume I’ll need stop to eat, drink, pee, etc. from time to time.

As for crossing oceans - there are some well-defined routes for small aircraft long mapped out. Once you’ve had some practice with longer distance trips over land you could probably follow one of those without completely outrageous risk.

Aircraft have compasses. A human would have the sun but that doesn’t always work…

I’m a human and I own a compass. Just sayin’…

I mean, can we only fly bare-ass naked? Or are we allowed clothes? And if we’re allowed clothes then why couldn’t we have a compass?

Likewise, a GPS devices exist that fit in your pocket.

I believe that the OP is trying to get a sense for innate human navigation talents, so it’s probably best to view our flyer as having been conscripted for a scientific test.

I think the difficulty of recognizing your house, land marks, etc from the window of a commercial passenger aircraft is due to looking out a small window, not being sure of direction, while multiple turns are taking place during approach and landing. I think much of this would be mitigated by being in control, knowing direction, and building experience.

Our mental ‘map’ or of our local is based not only on landmarks and physical maps, but our most common approaches and orientation. When I picture a map of my city for instance, I think of it with north being up. The configuration of landscape, roads etc is not as recognizable from unfamiliar angles or approaches. If you only ever approach a feature from one direction you may not recognize it immediately from a new direction. Experience remedies this.

I am pretty good with direction, such that I usually have a good sense of where North is. But I know this is not innate, but based on Sun, land marks, patterns. There is a reason that a compass is an important tool for navigation, no matter the medium of travel.

TL;DR:
I think the answer to the OP’s question is that superman style flying would be like any other medium for human navigation. Familiar routes are easy, new routes would require experience and or tools.

Iron Man needs all the reaction mass he can get.

My Superman fantasy is flying in space and exploring the solar system. Starting from Earth, I’m confident I could find my way to Venus, Mars, Jupiter, and (maybe) Saturn. I’m less certain about the other planets, and I wonder if I could even find my way back to Earth after blundering around looking for Uranus and Neptune. 10 light years out, I doubt I could even find my way back to our sun.

You’d need to be able to haul a long-term life support system with you. (For that matter, recent versions of Superman have him needing to carry at least an oxygen supply to fly in space, but he has super strength and by the terms of the OP you don’t.)

Assuming that, as Superman apparently can, you can accelerate and decelerate almost instantaneously with a top speed of several thousand miles per second without suffering the obvious physical consequences, I would think it would be quite easy to get anywhere on Earth quickly. New York to Phoenix: Say you take three seconds to fly west to the Pacific, then turn back southwest for a second and a half, go down low enough to spot a city and go see which one it is; that will take maybe ten, fifteen seconds. Then another half-second to go a few hundred miles in what seems like the right direction and check again. You might need to repeat this process a few times, but we’re still only talking about a few minutes. You’d need a general knowledge of the geography of the area you’re traveling through, like where the big cities and major landmarks are in relation to each other, but you wouldn’t need any sort of superhuman memory.

That was covered in one of the movies. Yes, it does process and recycle waste, at least liquid waste.

By going in a constant compass heading, which is not the same thing as a straight line (but which is probably easier to do, anyway).

Any of the planets out to Saturn is easily naked-eye visible from any of the others. And if you’re flying fast enough to make the trip in a non-boring amount of time, you mostly wouldn’t need to worry about orbital mechanics. Even at ten lightyears out, Sol wouldn’t be too hard to spot, if you’re familiar with the constellations.

Back to the OP, it’d be easy for destinations on major bodies of water (which most human cities are). Want to get to LA? Go west until you reach the Pacific, and then follow the coast until you can see the brown air. The only part that’d be at all tricky would be knowing whether to follow the coast north or south, but Baja California should be pretty recognizable. And even absent something like that, you can use what’s called the Principle of the Deliberate Error, and aim for a point that you know is (say) north of your target, so you know that you need to follow the coast south.

What constellation is Sol in? I’m quite familiar with constellations, but only as they appear from Earth. I’m sure I could find Polaris or Sirius, but Isn’t Sol going to be in a different constellation depending on what direction I am 10 light years out?

It’d depend on which direction you fly in. And the way you’d recognize it is by finding a constellation that had a star in it that you weren’t used to.

At ten lightyears out, a few stars, like Sirius and alpha Centauri, would be significantly out of place, but most of the stars that form the shapes we’re familiar with are much further out, so would only be slightly distorted.

Are you confident you could do that? I’m not.

From Alpha Centauri, it should be easy to find Sol. Our Sun would appear as an extra star in the W-shaped constellation Cassiopeia, making it into a zig-zag.
https://www.learnastronomyhq.com/_Media/sun_from_alpha_centauri_med.png

The OP is basically describing my first MOS in the army.

“It’s got a filtration system. You could drink that water.”

To add to the answers already given by others:

Sol is - by definition - not in any of the constellations. Constellations are not defined by being in a particular neighborhood in our galaxy. They are defined by their appearance from Earth. If you look at the stars of a given constellation, and you pick two that look close to each other, it could well be that those two are the most distant from each other of any pair of stars in that constellation. Once you go any appreciable distance from Earth, the relative positions of the stars will change, and once you’ve gone far enough, the angles will be so distorted that the constellation is no longer recognizable.

For example: eburacum45’s post would be correct, if and only if Alpha Centauri and Cassiopeia are on opposite sides of Sol, because that’s the only way Cassiopeia would look the same from both Sol and Alpha Centauri.

(If anyone thinks I’m wrong, PLEASE correct me!)