4 years old child enjoys balloon flying on air,paper flying in fan he makes a paper boat keep it straight to fan enjoys moving to side again he brings it straight to fan,he repeats the same for balloon also is it normal if not what is the problem he is doing it repeatedly and how to distract him.
Its normal. He's trying to make sense of the world around him. This should be encouraged. If you google for "preschool science air" you will find some activities that you can do with him. For instance:
This page shows how to link what a fan does with breathing, music and the wind.
This page helps show how aircraft use the air to fly.
Young children often go through phases of fascination with random objects or phenomena. The fact that something flies is a pretty cool quirk or anomaly in the physical world they've come to know.
My mom told the story of how when my eldest brother was a toddler, he would sometimes pull Kleenexes out of boxes for many minutes on end. With each Kleenex, a miracle occurred: it came right back, ready to be pulled out again! My mom complained to her mom that she wanted him to stop making such a mess. "Why?" said my grandma. "It keeps him entertained and it's cheaper than any toy."
And no, the fascination did not last into adulthood. :)