Perhaps in the interim you could have a new battery installed in the old MacBook Air. That would potentially also improve its resale value once you buy a new machine.

I also await the upcoming 2016 MacBook Pro refresh as my own MacBook Air (maxed out specs, 2012 model?) struggles with my daily computing workload. CPU utilization hovers circa 50% all day and often slams into 100% for many seconds for video clips, app startup, etc.