When in an LTE are and connected to WiFi as well, does data transmit through the WiFi or the cellular carrier? I use Verizon, Thanks

Wifi always take precedence over cellular data in iOS. However, when running on the internal battery, wifi gets turned off when in sleep mode, but cellular data does not. Anything using data while the device is in sleep will be using cellular (when plugged into an external power outlet, the wifi radio will stay on, even in sleep mode).

Verizon has nothing at all to do with your wifi connection - they literally are unware of it. The only data traffic over your iPhone they have any knowledge of is that which passes over their network and through thier servers on their cellular network.

As long as the phone is not in standby mode unplugged, WiFi takes precedence.

Can someone on the Verizon network tell me if they see both the LTE indicator and the wifi indicator when you have wifi on in an LTE area? One Verizon tech told me to exchange my phone and another said it was supposed to work that way. Seems odd to me because when in 3G coverage you do see both indicators.

You will see either the the LTE or the 3G or the WiFi indicator, depending in which you are connected to.

it depends. "most" data goes thru wifi on a priority basis.

exceptions: visual voicemail or any kind of carrier updates, - cellular only.

2. if wifi breaks momentarily, then the next data packets will be router over lte. now you may not notice it because wifi may sporaidcally turn on/off and so your phone would keep switching.