I like the LT-40 but then I haven't tried any other trainers.

My 7-year old is keen to learn to fly as well, but I have told him to wait until he's 10. My reason is that he and most other 7-year olds I know get distracted far too easily to keep flying the plane when it is up there. They don't have enough perspective to realize that the plane needs their complete attention and that it is a dangerous thing to lose control of it.

I also notice that when my son "flies" a simulator, he just can't keep himself from overcontrolling. He cranks the sticks all over the place, no matter how often I remind him to "use small movements". I think perhaps a 7-year old still lacks the manual dexterity to just stroke the sticks.

Anyhow, in the meantime my son comes and helps out at the field, and we are getting into building planes together - plastic and wood. By the time he's 10 he will have some idea of what goes into making a finished product and will have learned to respect that effort enough that he won't want to smash it up just to see what it looks like...