Two airplanes landing at the same time with close proximity

It's an optical illusion. The planes aren't really that close together. The person who shot the video is using a telephoto lens and is zoomed way in. This compresses the space and flattens it out so it's hard to judge distance. Also the plane in front is smaller than the one in the back which heightens the illusion. It's a really cool shot!

Comparing the engine sizes or counting the windows really shows that the back plane is probably double the size of the front plane.

Cool illusion.
- The one in back is a larger 737, the other is a smaller Embraer.
- Definitely the windows, but recent planes have gone with huge turbines so it's not the most reliable tell. I don't know Airbus well but the turbines on a 737-800 or Mac are pretty big compared to a - 300 or A320
Wait a minute, are you telling me that the hobbit actors weren't really that small?
- No they were, Peter Jackson just had his actor's legs cut off for the movie
I mean, it's rare enough that 2 planes land at the same time. They are definitely "close" but probably some 200m apart.
- It’s not as rare as you may think. I used to work at a weather service office located right near the end of one of the runways at IAD and it would happen a few times a day if the airport was busy and the winds were such that they were coming in from our side.

Is this standard procedure or an emergency situation?

OMG I wasn't expecting this much answers! Thank you all 🙏

SOP (like 99% sure). Many airports have parallel runways with more than enough clearance for two simultaneous landings. I have been a passenger in this scenario at least four times that I can think of, and I don't fly that much. I think those were in Denver, SFO and LAX. I don't recall there being any situation that would be considered an emergency on any of those.
- Yeah, this is SFO and these runways are 750 ft / 230 m apart. Definitely not a lot of room for error, but the telephoto zoom makes this look a lot closer than it really is
The runways are likely pretty far apart. Telephoto lenses compress depth and make objects appear closer to each other. It's why telephoto lenses are used for portraits to make facial features look more attractive and with slightly less depth.
- Well you use 50 mm (in the old system) because that was considered the "correct" perspective. Less would give you the fisheye lense distortion.
So the Alaska is a e175 which is about 70 people vs the United which is about 170 people. It looks close because of the angle and some camera tricks. Landing on parallel runways happens all the time.

They are called Precission radar monitoring approaches and they start doing them when things get super congested. Requires us to listen to another radio so atc can tell us to break-out if someone crosses the no go zone in between the runways.
I've done this (sitting in a passenger seat), it's normal. This video is a bit of an optical illusion, the planes are nowhere near as close as they look.

There are certain airports where it's standard procedure.
- Landing an airplane from a passenger seat takes mad skill! Respect!
My thoughts too. I figured that the FAA would prevent this from happening for any reason except emergencies

Edit: c'mon folks, I'm not asserting that this is an emergency or that this is against regulations. I thought it was, but if this is a normal landing then it's simply a surprise to me that it happens.
Likely just an issue with the perspective of the video, I bet these planes have plenty distance between them if you were to see them from the front
It looks dangerously close due to the camera lens.

In reality it wasn't.
That has to be an emergency. I can't see how any pilot would risk it unless they had to.
- The runways are probably 300 m apart.
Not necessarily standard, but not likely an emergency. Loads of places have the setup required for parallel landings / takeoffs, it's just usually more efficient to have them alternating

Here's a list of the places that have parallel runways (bottom of the page)

Well, now I need to see commercial airplane drag racing.

SFO

I'm more concerned about thos birds flying around the airport.

This needs a Strauss waltz as a soundtrack...

Butter.

Thought they were gonna crash like 5 times

It's a perspective trick - they're not close as you think they are, and the United plane carries more than double the passengers of the closer Alaska.

Another cool thing to think about is how like, this video of two planes landing can create a bunch on interesting discussions, i mean, just look at all these comments!

I knew it! I thought it to be impossible that planes can fly that close with each other without affecting each other. The air pressure (or whatever) would be affecting the flight of another plane if they are too close with each other.