From a few years back:
Most aviation finance companies are actually just brokers, such as AOPA, Dorr, Air1oans etc. There you have to do fully conforming loans and have all your ducks in a row. Meaning, they don't care about your assets, they care only about your taxable income. Best is to find a smaller bank that understands aviation and will actually carry your loan on their books, as they will be more flexible and can "read between the lines".