Also, you really need to develop technique to deal with internal stress in the plexiglass sheet. For a 1/4" panel we'd start at 3/8" and using "good" quality double sided tape keep machining small cuts and flip the panels alot (important to release internal stress and give you a flat panel before you router out the wire paths). Water based coolant flow will keep the heat down.
If you use cast acrylic instead of plexi, there's less need to worry about stress buildup, it machines really nicely. No need for flood cooling either if you keep the cuts nice and light.
Choowy, if you ever decide to go down the backlit/edgelit route - it'd be worth getting a quote from one of the many CNC shops offering their services online. I've found the prices to be far more accessible than I thought they would be.
Hey Wasp! That thing looks awesome - I bet there's a real sense of occasion when you climb into the pilots seat!
EDIT: Formatting