tango - airlines often don't own their own aircraft. They are often managed by lease companies or large finance houses. Any debt that EZY have as a result of buying aircraft could be structured in any number of ways. Just like every other airline.
Where EZY do have an advantage is:
1) Buying in a recession. Boeing and Airbus are twisting each others arms and giving each other chinese burns in their squabble to supply EZY. You can bet they get their aircraft at a VERY good price because they are buying when nobody else is.
2) EZY are bulk buying. An order of 100 a/c with a further 100 options is a large order. Discounts that only the likes of LH, BA and AF usually see are going to be on the table.
So we have bulk discounted aircraft sold in a buyers market.
In five years time those 737-700's will probably be worth MORE than they were bought for; such is the nature of this business and the business cycle. Fancy that - aircraft as an APPRECIATING balance sheet asset!
All the above pertains to Ryanair as well and possibly more so.
Ben.