Reading this got me thinking so I called my State Farm agent.
Airplane parts and tools in the garage: Personal property, covered under homeowner's policy, at replacement cost.
Airplane parts and other stuff in a storage unit: Ditto.
Completed airplane: Not their problem (but she's looking into whether they do aircraft or not).
Life is good. When needed (like when I move it to a hangar) I'll get additional builder's insurance, but right now I don't see the need for it. That said, we'll be taking a tour/inventory of the house this weekend to see if the total coverage amount on our homeowner's policy is high enough, or if we need additional coverage for jewelry, guns, electronics, etc.
But the big question I have is this... Suppose I have the wings and fuse nearly completed and something happens. Will any policy cover replacing it with a QB instead of a regular kit? I'm certainly not going to be satisfied with having to start from scratch. I'll have to ask that question of my agent as well as Jennifer at NA.