Is there a known issue with MBAirs and wifi connectivity? The GF's MBA won't reconnect to any wifi that it has connected to in the past. I thought it was just an issue with the 2wire modem she has at her place, but the MBA has the same issue at my house. Once I connect it, it won't reconnect after sleep. I have to manually turn off wifi, click 'join', then pick it out of the list. My 2 MBP's has no issues whatsoever reconnecting to my wifi after sleep, restart, etc. I removed the preference files they'd rebuild, no avail. Suggestions?