system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do aircraft cockpit windows only face upwards?

I get that the pilots need to see the sky above them, but don't they need to also see below? In photos, it seems pilots can barely see the runway when landing, and when flying cannot visually scan the horizon below the aircraft.
gpt
Pilots don't need to look down for the same reason drivers don't need to look under the car while driving: once a threat is "under" you, it's too late to do something about it.  And most threats come from ahead and from the sides.

It's not a bad comparison since, during landing, a plane is not much different than a car.  Finding the runway and lining up with it happens well before landing and requires looking ahead, not down.  Any "potholes"/threats on the runway are only relevant if you can dodge them so, again, you need to see them long before you hit them, not when you're on top of them.

[edit, based on exceptions that others have mentioned below: some helicopters, and older bombers, have wraparound windows or see-through floors precisely because they DO need to see "under".  They are landing vertically or need to be above the bombing target.  Those exceptions prove the rule.  Standard planes have no such need.]