How hard is it to get a private Sallie Mae loan?

My husband and I are interested in sending him to flight school but we'd need to get funding. The school he's going to attend works with Sallie Mae but they said that he might have to have a cosigner unless he had great credit. We don't really want to drag someone else into this with us so we'd like to do it on our own. How hard is it to get a private Sallie Mae loan? The school that he's attending doesn't qualify for federally sponsored loans.