Who has used a Mophie case on your iPhone while flying?

[MicheleStapleton]

I'm in Maine where it gets pretty cold; on my flight earlier this week my iPhone battery was down to almost 20% after only one Mavic battery. I'm reading talk about using a Mophie case attached to the iPhone to extend its life/possibly shield the iPhone from getting so darn cold so quick, but I'm not clear if folks are thinking out loud or if they are actually successfully doing it.

If you've don't that, how did you hook up the Mophie ? The cord that attaches to the iPhone is lightning but the Mophie takes a micro USB.

Thanks!