Weed can't be smoked in public, or anywhere smoking is prohibited.

https://www.sftravel.com/what-you-need-know-about-legal-marijuana-california

No where in public, which is a good thing!

OP isn't asking to smoke in the airport.

OP, go on http://maps.google.com and type in cannabis and see if there are any places near the airport. There are two kinds of places (medicinal and recreational). There are one or two recreational smoking places in the San Fernando Valley, but that's too far for you to go.

There appear to be four stores near the airport, but you need to call them and find out what type of ID you need, whether they sell to people out of state, under what conditions you can smoke on premises (if at all). Most places just dispense cannabis, they don't have places to smoke. You're better off with edibles (MadMen has them).

Also a good thing for his next seatmates.

OP did not ask where to buy weed. He asked where to smoke, so maybe he is bringing his own. And yes, there is at least one smoking area inside LAX.

Airside, inside security there’s a place to smoke? Where?

<<<And yes, there is at least one smoking area inside LAX.>>

Im pretty sure any smoking area inside the airport does not allow marijuana.

LAPD have said they aren't enforcing any anti-marijuana measures inside the airport. So, I guess if nicotine is okay, maybe bud is too. I see people in that smoking area with vape pens, hard to know what they're smoking.

However, if OP is bringing his own, he's got to get rid of it before going back through TSA checkpoint - they are not amused if they find it.

Yet again, it would be great it OP had his city of residence in his profile. If this is a domestic flight, say, from Colorado, things are probably okay. But again, going back through (federal) security at the airport...well, people say they are successful at getting vape pens and cartridges through but...not sure I'd risk it myself.

Some terminals used to have "smoking gardens", but I don't recall seeing any lately, although admittedly I am not looking.