Can I add more RAM to my MACBOOK Air

You cannot.

RAM is soldered in on all MacBook Airs, from the very earliest Intel-based models to the very latest M4-based ones.

No. That is not possible

"Can I add more RAM to my MACBOOK Air: I want to increase my RAM."

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Adding More RAM:

No. So, take this as a learning experience, next time getting an amount of RAM that will meet your expectations.