I can tell that it's bungled the handoff between one tower to another. When this is NOT an issue, trying to put it in airplane mode is almost instantaneous. When it IS an issue, airplane mode takes 30 seconds to fully drop everything.
From what I understand, this is fairly common to Samsung phones. I have owned the Note 3, Note 2 and Galaxy nexus, but never before did I travel this frequently for my job. Now that I'm traveling and having to rely on this hunk of ****, I'm going to be dumping it as fast as I can.
I also have an iPhone 5S for work, which I hate in every way imaginable except one, and that is that it actually does its job and hands off from tower to tower correctly without requiring reboots or disabling the network.
Hopefully the LG G3 is an improvement, because this is ****ing maddening.