He is right about the bulk discounts being more about cashflow than bank loans though.
Sorry, I just don't believe you.
I run a business. If I needed cash and had a choice between
(1) borrowing from my bank at X%
(2) borrowing from my customers at 3X%
guess which I'd do? And it wouldn't really be my free choice, it would be my duty under company law to maximise shareholder value by taking the cheaper option.
I would only be borrowing from the customers if the hank had turned me down.
(Actually I do borrow from some of my customers. I make them pay in advance because for the amount of business involved it's not worth the hassle of doing credit checking and buying insurance and taking advice from foreign lawyers etc. If they don't want to pay in advance, no problem, I won't do the work, I can find other things to do. But that doesn't apply to flying lessons which are much more of a buyer's market.)