Darkpet, you are quite right. A lot of real world airlines "own" their planes technically speaking, but at the same time, they owe a lot of debts, in terms of loans, bonds, and other instruments of financing. That is the financial leverage of a company. Not many of the real world airlines could afford to use 100% owner's equity and retained earnings on all their aircrafts. For those that could afford, might not choose to do so, for whatever reasons they base their decision on. The planes are listed as their own, but fact is, the invesment on the planes might not have been paid off.
As pointed out, the lease profitability depends on the lease rates, and the lease rates have to be able to cover the maintenance costs in order for the owner to make a profit. That said, the lease rates should be larger than the maintenance costs. Since all other costs are the same, owning an aircraft should always, under normal circumstance, be more profitable than leasing one.
The issue though is the investment needed. In order to buy a plane, you need to pay the whole amount up front, while the leases pay for themselves. For the same type of planes, you could probably get 5 to 8 on lease for the amount you need to purchase one. That is the difference in initial investment. Basically speaking, owning requires a much larger initial cash out-flow, but gives you a larger net cash in-flow in the service life of the aircraft. Owning also gives you the salvage value when you retire your aircrafts.
In terms of company value, you get value from the aircraft you own, and the cash (ie. profit).
If you own the aircraft, it is factored into your company value. All your takings would also add to your company value.
If you lease the aircraft, the lease rate is a monthly fixed costs, which would reduce your cash, and thus your company value. Your net increase in company value should be less on a per aircraft basis, given that the aircrafts operated are identical, and they are being operated in the exact same way.
Two points you really need to learn and get straights are...
1. Profit and Return are two different concepts, with completely different meanings.
2. Life is unfair, and the best survive.
As I have said before, you are not helpless. Please do not victimize yourself. If you think that the leasing model is the better one, go for it. There are plenty of people with an opposite view, and they have voiced their opinions through telling people not to lease aircrafts. (Well... or maybe those are the ones that think leasing is good and want everyone else to choose the worse path... who knows?
)