What is the best way to find a owner of an aircraft. For example, if you search in a aircraft register, you simply find the aircraft operator, not the owner. Is there another way?
It all depends on what kind of listing you look in. Many publications list both, and so do many countries' official (online) registers. The US civil register online seems to list owners, to name one.
Scramble prefers to give operators, as that relates to the appearance of the airplane (spotters generally care less about which bank owns an operators' aircraft).