Please do not use ALL CAPITOL letters when you make a post. It makes it look like you are shouting.
Now, you need to tell us some more important information:
1. What exact MacBook Air Model do you have?
2. What exact Mac OS are you running?
3. What EMail program/client are you using?
I have a mid 2013 13" MacBook Air running the latest version of Sierra, OS 10.12.6. I use Outlook 2016 as my EMail client, and it lets me know when I have a new EMail.