How common are aircraft partnerships compared to outright ownerships?

Joe - Great that you're looking into buying/co-owning a plane. FWIW, it
took me about six months to find both a set of partners and a plane. I
joined the Cardinal Flyers Online when I first started looking and that
was a source for a couple partnership contacts. Then again, I was
looking into a Cardinal at that time so it made sense to go with CFO.
However, groups like the Cherokee Pilot's association would be good as
well since you can get some local contacts. It turns out that one of my
current partners was a guy I'd met in a ground school and he knew
another guy who was interested. End result: a 3-way partnership in a
'71 Arrow and things are working out great.

Ask around your FBO, folks at the airport, and just about anyone you run
into. Be patient as the process can take some time. Good luck!

Jack Allison
Arrow N2104T