In this hypo’ the only ability this person has is the ability to fly. Said person would find it nearly impossible to navigate destinations wouldn’t they?
Like, they couldn’t just eyeball it from New York to Phoenix?
Why couldn’t they follow the highway system or use a GPS?
If I was leaving NYC for Phoenix and trying to keep it simple.
I would take Rt 80 to 55 to 44 to 40 which gets me to Arizona. Then in trying to keep it easy. pick up 17 in Flagstaff to take me down to Phoenix.
There are shorter ways, but I am going for easy Navigation.
For the record, long ago I drove from San Diego back to NJ using this route in reverse using only a Rand McNally Road Atlas. I was on Rt 8 most of the way to Phoenix. Once I was back in NJ, I got onto 287 off of Rt 80.
I meant to imply with no GPS, and going in straight lines from point A to B. (I thought of using highways as well)
So are highways acceptable or not?
If you want a true straight line, learn how to navigate like the old school pilots. Think Lindbergh and early passenger/mail flights.
It involves taking a lot of sights to stay on course.
Luckily for Superman he has Super-Vision so he could ID landmarks from miles away to help him navigate.
High speed wind in your eyes would make seeing difficult.
It’s acceptable, it’s just that in my mind “like Superman” means flying in straight lines. 
Last I checked goggles or a helmet with a visor wasn’t a super power.
Ok goggles are allowed.
Assuming flight ability, and no other superpowers (and, as the OP later specifies, with no GPS), then you’d need to either (a) follow highways and landmarks, or (b) use a compass and/or celestial navigation. Either way, you’d likely also need a good set of maps.
Flying “in a straight line” like Superman, with no other assistance, would require knowing the exact direction needed (and taking into account the Earth’s curve, unless it’s a very short flight), as well as the exact distance needed – which you’re only going to get if you also have the superpower of perfect directional sense and perfect knowledge of the Earth’s geography, or using tools like maps and compasses (and calculation).
Well there you go, I could get to Phoenix with nothing more than a helmet and a Rand McNally.
What’s my flight speed?
It is trickier to follow, but the highway route could be as little as 2431 miles. And almost straight.
The route I described was more like 2560 miles.
Fly high enough to take readings from the stars. How hard could it be?
This assumes that Superman also has the ability to tolerate very low air pressure. If not, he would quickly lose consciousness at high altitude. That would mess up his navigation somewhat.
Exactly. Go up about 5000 miles, you should be able to see your destination. Or a waypoint, if your destination in around the curvature.
And Superman doesn’t need goggles! Sheesh. He can bounce bullets off his eye, you think a little wind would hurt?
But that does raise a question - how fast does he go? (This applies to Iron Man, too.) Even if you’re flying Mach 4, it still takes quite a while to get anywhere. Does Superman get bored flying for 5 hours with his arm out in front of him? Does he need an iPod to pass the time? What if Tony Stark needs to stretch his legs?
Yeah, as others said, once you get high enough, you can see all of America at once, and it isn’t hard at that altitude to fly to where you want to go.
That being said, though, there are some people who even from a high altitude might mistake Phoenix for Albuqurque or vice versa.
In one of the movies he circumnavigates the Earth several times in a second. I believe the canonical answer even in the comics is that he can break light speed, so for any terrestrial navigation he’d have to purposefully go slower lest he destroy his destination with a shock wave.
This is much more interesting to consider, I think, because Tony Stark is a mere mortal. In the first Iron Man movie he apparently flew all the way to the Middle East or some such place after he completed his first red suit. I’m guessing he’s a got a great GPS in there, so I buy that navigation isn’t a problem. But assuming the thing could go Mach 2 and bit that would still take a while, so…
Does the Iron Man armor have a way to process human waste? Can it recycle it like a Dune-style stillsuit, or did he just wear some Depends?
You can basically experience this in Google Earth VR… and yeah, it can be fairly difficult to navigate by eye unless you can fly way the hell up, so far up that you can see a good percentage of the US. Highways help, as do rivers, but it can be pretty easy to lose track of them if you’re going a good distance. Good luck doing it in a country you don’t know well.
“I knew I shoulda taken that left turn…”
I thought of that and tried it. I was doing it when you posted this.
I started in Connecticut. I recognized the Appalachian mountains, and knew when I got to Kansas/Nebraska. When I got to a place that looked like it could be Phoenix I checked to see where I was. I ended up in El Paso.