Hi Charles,
I am not with Laminar Research; just a flight simmer from down under.
Welcome to X-Plane.
X-plane 11 is a totally different package to X-Plane 10. Unles the XP10 aircraft you have have been updated for xp11 there is a slim chance that they will work in XP11. Have a look at the following link found at https://www.youtube.com/watch?v=V4RjIxrhkXs for further information.
When you install XP11 it does not overide or replace XP10. You will have two different packages, provided you follow the recommended locations for the installation ie don't install within your operation system files. The installation needs to be a standalone directory
In relation to KLAX airport, download the demo version and have a look for yourself. I understand KLAX is the airport used in the demo. The full version of XP11 is the same as the demo version. The demo has a fixed location and a fixed time limit once you select the aircraft of choice to fly.
When you purchase XP11 you will be provided with a "long" product key number to apply during the demo version "bootup". When applied correctly, at the prompts, the demo version becomes the full version.
Good luck
Glenn