Everyone arguing their corner and repeating the same things each time - this is right up my street!!!
Take the share out of the equation - If I have a C150 and buy it for £16,000 fly it for 1,000 hours and put some cash to one side to cover a new engine, do I sell it for £16,000 and give them the engine fund? no i sell it for a figure commesurate with what it's now worth (say £14,000). It may equate to what I have in my engine fund, it may not.
If I'm buying a share in an aeroplane I'll look at it's value and offer a share of that. If there is an engine fund then I'll count myself fortunate, I won't buy a share of the cash in the fund though. Someone has already paid that for the time THEY flew it.
I agree with Bose and Chilli. An aeroplane isn't worth more because it has a fund, it's worth LESS because it DOESN'T.