Risa

I think most species probably align themselves to either the galactic plane or prominent orbital plane of the local star system.

the "up" & "down" directions would be completely arbitrary, though. there's no reason to think everone would decide on a standard for those.

and species without that certain sense of appropriateness, or an overt dedication to logic, would likely not bother with a standard orientation. and especially when in orbit over a planet, I think everyone would orient their "down" towards the surface.

Most realistic depictions are from the Klingons because tactically you should always face with your weapons oriented towards everyone at all times, including your allies.

This is why the Borg uses cubes and spheres.

For a ship that never needs aerodynamic control, any shape at all will do so why do they all look like airplanes?

The Borg are the only ones who seem to get this.

This is why I appreciate the scene in Undiscovered Country where Kronos One glides into view, seeming to align itself to the Enterprise's orientation.

https://youtu.be/AkqZja1IBfk?t=129

Actually, space in general is mostly 2 dimensional, in that all the interesting stuff generally takes place on some sort of almost flat plane. A star system is generally on a plane, so is the galactic system, and for most planet+moons too. They just tend to be different planes so for ease of communication you will probably just align your idea of down with whatever the most convenient plane is. This of course is ignoring what gravity down is, as that changes as thrust does.

And as for ship alignment, yeah no one is going to worry about that till its time to dock, at which point the lighter vessel will likely change their orientation since its easier and takes less energy. Spaceships are not going to be within human sight range of each other most of the time, even being in relatively the same are. Space too big and getting ships close to each other is dangerous!

But in media that fucks with people's idea of meeting and seeing each other so for convenience of not confusing the audience you don't see that level of realism often.

Every Episode of Popular Space Show

What’s weirder to me is how ships are oriented to a planet. Especially if they left atmosphere just a while ago. So they left the planet and then decided to orient the ship and align the vertical axis of the ship with the axis of the planet just for looks.

Their pattern indicates two dimensional thinking...

https://youtu.be/RbTUTNenvCY

I think in this context no ship would ever approach nose-to-nose. That's just for the viewers to see. I'd wager no two ships would come into less than around 1-5 km of each other if they weren't lining up flight paths for shuttles or docking. It's not like they need to "stand up" next to each other and "talk".

They would probably have formations they would assume while in transit or stopped, so it would probably be normal to cross paths with a formation flying upside down or in a perpendicular axis.

In case of just meeting and talking, they'd probably do it from wherever they happen to be, very far from each other, flying towards different destinations.

I don’t know, I think it would look fine to me.

Have you all forgotten that they directly addressed this in the show? https://youtu.be/Q9W7pvOLxmQ

Right, so, let's talk naval ships from the age of sail. There's no need for two sailing ships to face each other also, but that's inevitably how ships will meet on the ocean. The HMS Enterprise spots the HMS Defiant. They plot a course towards the Defiant. Defiant will eventually spot the Enterprise, and will alter its course. Both ships will meet with their bows facing each other. Same logic applies with spaceships, with two issues:

1. There's actually no need for two spaceships to meet in order to talk or transfer people. I'll hand wave that away saying that's standard procedure, as the cost in time and energy to go from the beaming range to visual range is negligible, and even in the 24th century it's a good idea for ships in the middle of the vastness of space be as close to one another as possible in case of emergency.
2. While both ships will change their pitch and yaw to face each other, there's no need to change the roll. This can also be hand waved - while there's probably a standard, absolute "up" (say, using the spin axis of the galaxy) altering the roll will allow both ships to use the same subjective "up".