Well, you can learn to fly on either size, but if the Thunder Tiger Trainer 60 ARF costs nearly the same as the LT-40 ARF, then I would go with the Thunder Tiger Trainer 60 ARF. It's bigger and more stable, Plus you can use the engine in your next plane (why buy another eh??). LoL, I know that most members will say get a 40 size trainer, but you don't have to follow the crowd (I never do lol). Any club will except (if you get it) the Thunder Tiger Trainer 60 ARF, and teach you to fly it. Since my LT-40 is the almost the same size as the TT Trainer 60, I slightly Modified it to fit a Thunder Tiger 61 pro (which you can get for under $100) and yesterday, it had its first flight and flew perfect. Here, members said that its overkill, overpowered, wings might fold, nothing went wrong LoL. My instructer checked it over before he flew it, and was happy with it. hes said that it's a perfect flyer on a 61, (though I won't do any power dives, even on any other plane for that matter)

And one more thing, DMcQuinn is right what he says...