i just spent a month in remote eastern oregon, out of cell range with my new iphone 14 pro. i turned off the cellular data, wifi, & bluetooth, yet when left 100% charged at night, it was near dead by morning. "Battery Level" chart in Settings showed a continuous drain throughout the night.
was this due to the GPS constantly searching? what should i do during my next visit?
That seems like a mighty fast battery drain, especially for a new phone. I've been using iPhones for years, currently using an iPhone 11, and I've never seen battery drain anywhere near that fast when not actively using the phone. Makes me think it is something other than just the GPS?
I would check to make sure you don't have some app running in the background? You can set things up so that it only uses the GPS ("location services") only when you are actively using an app.
And yes, when an iPhone is in Airplane mode it does turn the GPS off.