The easiest plane to learn to fly? I guess if you consider complexity of operation the 150/152 is, in my opinion, the easiest. If you asked me this question 50 years ago I would have said the J-3 Cub or Ercoupe. In fact, given a competent instructor, all small trainers are similar in difficulty but are different in the technique required to fly them. I would say the "easiest plane to learn to fly" has more to do with the instructor and less to do with the aircraft but, who am I to challenge the authority of "the internet" on the subject.