If you are one of those flutists who do not want to play with 'Airy sound', the first thing you have to do is to close the 'embouchure hole' only 1/4 or maximum 1/3.
To do this, you have to relax your embouchure to make your upper lip be able to cover more. The flexibility is needed for 'the sonority'. Try to put some air into your cheeks.
This is the first principal to play with the 'Beautiful Sound' !!