Just as a guess, I'd say it would be more likely to see celebs on a route where it is difficult or impossible to get a reasonably priced charter. LAX
is easily done with Netjets or some equivalent. LAX
not so easy.
On a slightly related note, I grew up next to Beverly Hills, but literally on the wrong side of the tracks. I saw celebs all the time at a big drugstore (now gone) before they had a similar place in Beverly Hills. If a visitor wanted to see someone famous I suggested the Baskin-Robbins ice cream store in Beverly Hills. No matter how rich and famous you are there is no way to send out for an ice cream cone. The whole experience is about being there.
With airports, the best part of travelling is NOT being at the airport, so celebs will either avoid them with a charter or disappear into the first class lounge at the airport and not emerge until the last moment, slip through the L2 door on a wide-body at the last minute and turn left. Mr row 47 will never know it happened.