My DS (now almost 2.5 years) was flapping his arms mostly in excitement since he was 6 or 7 months old. He still does, but not as much. I was worried because he was late with most things, like sitting up, crawling, walking, talking, and even pointing to things. I was always more worried than my DP, so I started asking questions around the 16 month mark, I thought he might have autism. We finally got to see a very good developmental doctor, who ruled it out, but he did diagnose him with global development delay and said he's got a few little quirks but they do not amount to anything to worry about, iykwim . So at the moment he is going to childcare 2 times a week (3 hours a day) to improve on his speech, which has been working so far and he's only been going 3 weeks. My advice is to seek answers if you are concerned. I'm glad I did because I started stressing so much it was on my mind 24/7. Lots of kids flap with excitement, and it means nothing, but sometimes it does, so if you're getting worried, ask the question to rule anything out. GL hun x