How do i get rid off the airy sound? Thx

Some suggestions:

- Lips pulled tight around teeth, reducing the length of the passage between the lips, causing a turbulent airstream?
- Front part of tongue raised, causing turbulent airstream.
- Upper lip too high, such that the upper teeth slightly intrude into the air entering the lip aperture, causing turbulent airstream.
- Jaw too much closed, such that lower teeth intrude into the airstream, causing turbulent airstream.
- Lower lip not covering approx 1/3 of the embouchure hole.
- Blowing down instead of straight ahead.
- Jaw pulled back so that the lower lip is pulled back from the upper lip.
- Blowing too hard or too gently.
- A really dirty embouchure hole.
- A flute with a really crappily designed embouchure hole.
- The crown cork is well out of position.
- The flute has a heap of leaks.
- Simple lack of practise that includes long notes with very careful listening.

... etc. Get a good teacher!

Thanks for asking this crucial question.
Thanks for answering.

You are most welcome. It is a pleasant surprise to have one of my answering posts appreciated for a change in this strange place.

my airy sound dissolved after grade one.

I don`t think I ever had one, but I think it is fair to say that clear flute playing comes a lot easier to some players than others, and also that some students are far more fortunate in having a teacher clued-up enough to help them avoid or quickly overcome such issues as `fuzzy` tone.