EDIT: misread the question.
An "Airy" sound can be due to several issues.
1- the reed you are using for the mouthpiece is too hard. Mouthpieces can VARY a lot by design. And based on the design is how you select a reed. Such as these differences ==>
http://www.clarinetperfection.com/clmpcTypes.htm
2 - the facing of the reed is longer than your previous one. In which case your embouchure probably is adjusted to it, and there may be gaps between the reed and facing which is outside of your mouth, which can provide an opening for air to escape.
3 - if a larger tip, you could be pushing much more air into the instrument, which if it is setup with a lower keywork height not for the amount of air, then you can get an airy tone in certain notes.
4 - The facing on the mouthpiece is off. The table could have issues, the rails could be uneven, etc. There's no easy way to tell other than to have a mouthpiece person check it for inconsistencies.
But it's probably either 1 or 2