Last week I updated my iphone 5 to ios8.  Everything with my P2V+ has worked fine before.  Now when I go through preflight everything connects fine.  Once I get 6 or 7 satellites I start up the phantom.  As soon as the motors startup I lose the wifi connection.  Could this be an ios 8 issue?  I am going to try my wifes phone, she still has ios 7.  

I have not suffered any loss in signal. Try getting the Wi Fi booster app.
Also make sure you phone is not connecting to other Wi Fi networks.

We have tested iPhone 5 with iOS 8, there is no such issue.  Making sure your phone is not connecting to other Wi Fi networks worths a try.

Iphone 6 with os8 and everything working flawless!

I made sure the phone was not connected to other wifi networks.  Any other suggestions?  I will try going to airplane mode and just selecting the wifi to see if that works.  I get a connection fine when on the ground but as soon as I start up the phantom the wifi drops.

are you losing the wifi connection completely? or just the video? My video would usually be ok while it was sitting with the rotors spinning, but once I took off I would often lose the streaming video. My other flight info and camera controls worked fine.

I would lose the wifi connection completely when I started the rotors.  It was fine on the ground.