Hi @vonbobo, I'm the project creator and in short, yes, Airplane Mode limits the signals in (and out) of the phone but does not block them completely. Unless you physically remove the battery (impossible on iPhone) you cannot be certain that the phone isn't leaking (cell, wifi or GPS) even when it's powered down.
As for your battery concern, after a solid month of testing my iPhone 5 lost between 8 - 11% of its charge over 8 hours inside the UnPocket™, compared to 5 - 8% lost normally over the same period outside the pocket (when the phone is on but not being used). Also I have one of the first iPhone 5’s that have just been recalled by Apple due to dodgy batteries so these should be worst case scenarios. But as mentioned, if you really want to conserve battery then switching to flight mode before putting your phone in the UnPocket™ won't hurt.
@sssss We're using different layers of metallised fabrics to create the Faraday cage. Sorry I can't be more specific than that for obvious reasons.
We never tested the UnPocket for radiation but it does definitely block all RF signals. As to whether or not these = radiation I cannot say.