This is a thread that is filled with wrong information. The website of the AG in CA is so easily found and has the information so prominently displayed, it is frustrating that no one bothered to even check it before offering advice or, frankly, asking this question.
Possession of a handgun in California is not restricted so long as it meets the FOPA storage criteria. Here is the exact wording from http://oag.ca.gov/firearms/travel
"California Penal Code section 12025 does not prevent a citizen of the United States over 18 years of age who is not lawfully prohibited from firearm possession, and who resides or is temporarily in California, from transporting by motor vehicle any pistol, revolver, or other firearm capable of being concealed upon the person provided the firearm is unloaded and stored in a locked container."
There is no issue with LAX so long as you have not broken the assault weapon or high capacity magazine laws and have the gun unloaded and in a locked container. See the aforementioned web page for the rest of the info.
The difference is that in NY and NJ, possession of any handgun, in any manner, is illegal for all, with affirmative defense provided for LEOs and permit holders (and other very specific instances). In CA, there is no such law.