I was not sure where to ask this question. The 1965 version with Jimmy Stewart is the one to watch. Everyone from the flick is gone now with the exception of Barry Chase and Hardy Kruger. Warning: Do not watch the piece of crap remake, best advice I have given in recent memory.
The author I think had an aviation background and spent a lot of time on the technical aspects of what they were doing. But what I am wondering about is whether the possibility of marching out of the desert having about a zero percent chance of success. This is a 200 mile trek across the desert with magnetic mountain ranges affecting the compass.
Water and exposure are big problems but they also point out that navigation would make it possible to "walk past the Eiffel Tower" and never see it. The unequal strides between left and right legs is mentioned.
200 miles indeed seems like a long journey but the character proposing the idea was a military man.
EDIT: Plot summary, major spoilers:
An old oil-company plane crashes in the Sahara desert. The passengers are mainly oil field workers plus a couple of military men and a couple other men. The plane is completely unflyable and their radio is broken also. It was meant to be a short flight -- they have for the 7 or 8 survivors 10 days worth of water and some pressed dates as cargo to eat.
They realize that no one is coming for them because it is unlikely they survived plus searching would be very hard. So they are on their own.
The only things being considered are hoping a plane will seeing smoke pots they are burning and marching 200 miles across the desert for help -- nobody thinks either of these will work.
The "big idea" of the film is that one of the passengers is an engineer who in fact designs airplanes and he quietly has been considering whether it is possible not to repair the plane, which can't be done but to take the broken pieces and create a new plane from the remaining salvageable engine and wings -- the original plane of course had a passenger cabin, etc. with twin engines; the new design will be a single engine and the passengers will be strapped onto the wing for what is anticipated to be a short flight. The design requires all sorts of improvisation.
No one thinks this will work either and the engineer proposing this is German which in 1965 was significant -- he is too young to have fought in ww2 and his youth is also a factor which makes the captain, played by Stewart who was in his late 50s at the time, both be skeptical and resent the challenge to his authority.
Despite the fact that no one thinks it will work, they have no alternatives and they begin. The engineer proves himself to be just incredibly, Mr. Spock-level competent -- he is able to solve all sorts of technical problems and eventually the new plane begins to take shape.
There are some twists that I won't spoil and some conflicts. It is very much worth seeing.
The military officer nonetheless decides to march for help -- iirc, he embarks early in the film, maybe before the construction is underway and returns barely alive. I don't think they give him beyond his normal water ration which maybe doomed the attempt to failure since he will have no shade. But also, others point out that he will almost certainly not be able to find his destination due to navigation issues.