That's a question no one can really answer yet. The skylake processors will have a better performance, but that doesn't mean the current processors aren't great. If you want to wait for an upgraded processor then waiting will be worth it in the long run. However it might be awhile before Apple updates its current line of MBPs, probably mid to late 2015. Personally, I won't be waiting. The current performance of the MBPs are great, good enough for me at least
You all should state why the 2011 Air is no longer meeting your needs. If it isn't then why not, if it is but you just want a new machine then I'd wait a bit. If you need the power, get one now.