I think I can now confirm this issue, and I believe it is much more widespread than reports may indicate: I see issues on both my iPhone 6+, and an older model iPad. In both cases I can see my WiFi indicator coming off (in the case of the iPad which does not have a cellular modem), or either dropping to just a dot, or switching to indicate LTE. Those drops/switches happen randomly and very quickly, and the indicator comes back on immediately. I really need to be watching the indicator in order to make sure I don't miss it. Frequency is roughly once every ten seconds to maybe once every 30 seconds. Since you really need to watch for the drop-outs, my guess is many people may have this problem but have never noticed it. In my case, so far, it seems to be mostly cosmetic: I do not really seem to lose connectivity permanently, and I don't notice increased battery drain. However, this afternoon my iPhone 6 lost internet connectivity entirely, both WiFi and cellular, and I had to do a hard reboot to get the internet back to working.
Bottom line: There is an issue with 8.1.1 and WiFi, and this needs to be fixed as soon as possible. Heck, even Google can make a smartphone OS that can connect to the internet reliably... 😉