From an insider prospective on the LAX shuttle flying, the schedule is custom made to be intolerant of any delay. The flights are underblocked and scheduled with 30 minute turns all day. I see very few, if any flights cancel for no pilots unless they time out, which does occasionally happen with all of the SFO ground delay programs. There are so few gates in LAX that even when we know in advance of a ground delay, we have to push and start racking up block time. Throw in any mechanical or weather issues and it just cascades through the rest of the day. Everything is just spread too thin in LAX...gates, block times, aircraft utilization, etc.