MacbookAir won't connect to WIFI

I have a MacbookAir bought in May 2014. Just this last week it's wifi connection has been spotty. Our internet and our router are function just fine - our phones, desktop, ipad, etc. all connect to the internet/wireless perfectly, no problems. However, the Macbook's connection has been spotty. Sometimes it will connect just fine, but other times it will not connect to our home wireless automatically. When I go in and choose our home wifi connection (which has always had the password stored), it will ask for the password or just say it can't connect and give me that box that asks about running diagnostics.

Is this a known problem with that generation of Macbook Air? I'm tempted to just take it to the genius bar, but I thought I'd ask here and see if anyone had any suggestions.