I'm on Sprint, and this is happening more and more as time goes on. It'll be on 3G, barely able to do anything, then I turn airplane mode on and then off. LTE shows up and I get good enough speeds to actually use YT. Is this an iPhone issue or a Sprint issue? I went to their troubleshooter in the app and it tells me to turn the entire phone off and on to deal with the issues. For the record, that does make it able to use LTE as well.