The time zone thing I think depends on 2 things: the planned travel time, and each child's personality.
We planned our flight to DL for very early in the morning eastern...8:25am flight. We had to leave the house at 5:30am to get to the airport in time to go through security, get breakfast, etc. We pretty much took DD straight from her crib to her car seat, gave her something to drink in the car and started driving. The timing served a couple of purposes...
#1 - we were hoping with how early she woke up, she'd take a nap on the plane. (She did)
#2 - the timing of the departure meant we were landing around noon in LA. Even if she hadn't slept on the plane, it would be her "normal" nap time (she's usually napping at 3pm est), and it would have been fine for her to fall asleep on the drive to Anaheim from LAX (it's at least 45 mins w/o traffic, longer w/traffic).
#3 - the earlier nap time (whether on the flight or in the car) would help her be ready to go to sleep at an appropriate west coast time as well.
Basically, leaving really early in the morning helped to preemptively reset her body's clock to the Pacific Time Zone.
It was more of an adjustment for her coming back to the east coast at the end of the trip than it was heading to the west coast. But even then, we did our best to work with her timing. We left LAX around 10:30am, and arrived back east around 8pm. Again, the flight was over her nap time so she slept on the plane. She was plenty ready to go to bed when we landed..the hard part was making sure she didn't fall asleep in the car on the hour long drive from the airport to home.
But each child's personality does play into this as well. DD is a great traveler, and always has been. Car, Airplane..doesn't matter, she's pretty easy. If she were more difficult, then that would factor into my decision making process.