Can you upgrade the RAM yourself on a MacBook Air?

Or any of the MacBooks? I'm pretty sure you can't upgrade the flash storage, which is a bummer, flash doesn't last forever. Not a huge deal, if you get a new one, it has Thunderbolt 3, that's plenty fast for any SSD. It'll be a while before USB is as fast as Thunderbolt 3.

They should give me a free RAM upgrade, otherwise it isn't worth over a grand. I want the Retina display, that means you need a newer MacBook.

It would be cheaper to get the cheaper MacBook, and then use one of the shitty apps to use my iPad as a display. Can't use the free one, doesn't work with the newest macOS, and it was last updated a year ago.

Looks like the newest Air, the RAM isn't upgradeable, soldered on. But the flash might be upgradeable, expensive though.

It adds $200 to upgrade the RAM. What happens if I have over 2k in the bank? I need 2k for a 1k laptop, over that, and over 2k. Got to keep 1k in the bank.

I need a real Mac, so I can use the App Store. If I login, I might get banned. I use the account on my iPhone, iPad, and Apple TV.