He was talking about SNA. Since you brought it up, I can provide some more information on public transportation. It is more based on weekday schedules.
I am not actually based in LA area, so these might not be the best options. However, I visit LA about once per month from the bay area, I did all of the options below. Generally it is not a good idea unless the number of people going is small.
LAX: One option is to take green line light rail to Norwalk (need to take a shuttle to the green line airport station), then Metro 460 to Disneyland, 460 is nearly all local and takes very long. It takes a little more than 2 hours, but most of the time is spent on Disneyland -> Norwalk (around 90 minutes). Total cost is $1.75... If you replace the 460 part with Uber/lyft, it is much faster. You can also do Flyaway (to Union station) + Amtrak (or Metrolink) + OCTA 43/543 (for Fullerton) or ART 15 / OCTA 50 (for Anaheim). It also takes about 2 hours, cost around $20.
LGB: Long beach 104 (to Norwalk / Wardlow) + OCTA 46. About 1.5 hours, cost $3.25.
SNA: As mentioned above, OCTA 76 (to MacArthur / Harbor) + OCTA 43/543. About 1 hour, cost $2 (OCTA's single ride ticket is valid for 1 hour, can be used for transfer, though I do not know if it is the intention...)
ONT: This one... too difficult...
BUR: You can take the train, either Amtrak or Metrolink (need a transfer at Union station), and then either OCTA 43/543 (if you use Fullerton station) or OCTA 50/ ART 15 (if you use Anaheim station). Cost around $20, takes 2 hours.
OCTA 43/543 Metro 460 is right on Harbor outside the door, OCTA 46 is on Ball near the TRAM, OCTA 50 is on Katella. In order to utilize transfer feature for public transportation in LA area, you need a "TAP" card which you can obtain on ticket machines for $1. For OCTA fare, you can use the app.
where is the Disneyland pick up for this bus, how much is it and how long does it take to get from Disney / Anaheim to LAX? This might be an option for me in the summer, as I'm looking for alternative shuttles now that SuperShuttle is gone.