My further response:
Physical possession of a vehicle is not necessary under California law. In the case of "Solano Concrete Co. v. Lund Constr. Co. (1976) 64 Cal.App.3d 572 [134 Cal.Rptr. 552", the court held, pointing to a Black's Law Dictionary definition of "execute"—" 'to make; as to execute a deed, which includes signing, sealing, and delivery; performance of all necessary formalities.' (Black's Law Dict. (Rev. 4th ed.) p. 676.)
Delivery is different for different things in California. There is a specific definition of "Delivery" when it comes to vehicles. Under Veh. Code, § 460 (definition of vehicle owner), and Veh. Code, § 5600 (transfer of title effective on delivery of ownership certificate and fee to Department of Motor Vehicles), a vehicle is considered "delivered" if all formalities have taken place (the signing of the contract of sale, and the certificate of title being changed into the name of the new owner and sent to the Department of Motor Vehicles).
Good luck to you.
IAAL