Sales Tax and Delivery

I'm curious if anyone has ever done this:

Purchase a used aircraft in California (my state of residency) and have it
delivered by the dealer to Oregon. There it will stay for 91 days and be
flown on occasion, then brought back down into California.

My real question here is "if I buy the aircraft in California and have it
delivered to Oregon, in what state does my ownership begin?" The tax law is
clear that as soon as I bring the aircraft into California, then I may be
subject to use tax. So, is it my aircraft when I make the purchase in
California, or when I receive the aircraft in Oregon?

r.