This little boy is day dreaming in class and imagines he is a jet fighter pilot and all sorts of heroes.. and finally is sent out of class and imagines he has a hatchet on his way to cut a cherry tree... Anyone know the cartoon?

There are two (maybe more) Chuck Jones cartoons that feature a boy named Ralph Phillips who daydreams. In From A to Z-Z-Z-Z he is daydreaming in his class. The other one is called Boyhood Daze where he is sent to his room for breaking a window. This is the one with the cherry tree scene at the end. You can watch them both here:
YouTube - Boyhood Daze (http://uk.youtube.com/watch?v=LZok9MavFpg&feature=related)
YouTube - From A to ZZZ (http://uk.youtube.com/watch?v=_IOvEo9f4bk&feature=related)