I think it just connects with the Green Line in Redondo Beach.

It will also connect with the K Line (Inglewood). Per Metro.net:

setting the stage for the opening of the LAX/Metro Transit Center, the C and K Lines will be reconfigured on November 3, 2024, and a shiny new station will open at Aviation/Century to connect riders to more jobs, local businesses and attractions.

The LAX/Metro Transit Center will be a game changer for Los Angeles; Metro riders will have faster, transfer-free rides between Expo/Crenshaw and Redondo Beach. It will also provide Angelenos and visitors a convenient, affordable way to get to and from Los Angeles World Airport.

How do I get there from Santa Clarita? There is a train that goes from here to NoHo, etc. But, does it connect with this new thing?

Took my daughter to LAX yesterday via car. It was a nightmare. Would love to have better way to do it.

Kinda sorta. Take metro link south at Sta Clarita Station. Get off at Norwalk Station. Go west at Norwalk Station on line C metro. Unfortunately, Norwalk Station (metrolink) is 2.8 miles from Norwalk Station (metro line c). Norwalk Transit bus number 4 between the two stations.

Best to just take a freeway flyer to the airport,