There are 5 airports local to Disneyland. LAX, SNA, LGB, BUR, and ONT.
I do not consider San Diego (SAN) to be local, as it takes at least 1.5 hours driving legal speeds to get from downtown (where the airport is) to Disneyland. And that's highly dependent on what time of day you get in and if there are events happening at the park. The train (Amtrak's Surfliner) is pretty amazing, but you have to get from the airport to the train station, then from the Anaheim train station (which is, bizarrely, in the parking lot of the Angels stadium) to your resort. (you can use ART or a cab for that...there are cabs waiting there at the train station, though as you walk off the train it looks like you are in no-man's-land).
Be SURE you have transportation fully priced out before you make the decision to go with an airport that is not LAX or SNA. Disneyland Resort Express (run by Gray Line, and is a coach bus) only goes out of those two airports. Super Shuttle goes from many others, but has a very different pricing structure for SNA and LAX than it does for the other airports. (and if you are pricing with SS, choose your hotel to tell them where you are going, do NOT enter the zip code, as using the zip code results in higher prices) I like Karmel Shuttle recently. Just don't choose an airport because it's cheaper, only to find out that your transportation costs will be much higher.