I last used the american flyers program. Very poor program, the only value of which is that you can renew your certificate. I'd recommend anything else to someone before that. They do give you a "lifetime" renewal for the enrollment fee, meaning you can go back and renew again, but it's not worth wading through their poor system.
Among other things, you're required to have x amount of time on each subject to show that you finished the course. I found that after spending an hour on a subject, often their computer wouldn't even show that I'd been logged on, or that I'd only been logged on for a few minutes. The result was that I spent a lot more time wading through things than I should have.
Additionally, much of their material was outdated, some of it flat-out wrong. Their emphasis is all wrong for a review, with far too much time spend reviewing fundamentals of instruction, and little time spent reviewing more important subjects. I'd sooner kiss a shedding cat before I'd deal with them any more.