>millions of flights have been conducted in the cell phone era without an issue.

First of all, this is not true. I have read aviation safety reports that cite consumer electronics as a contributing factor. Second of all, the fact that no major mishap has been attributed to consumer electronics is probably due in large part to the controls in place. There may be a few individuals who don't care about safety who disregard the rules, but as long as the overwhelming majority of passengers comply, the chances of an incident are dramatically reduced.

Aviators are tought a "swiss cheese" model of mishaps: there are safety precautions in place (equipment, procedures, etc.) to prevent mishaps, which you can visualize as slices of swiss cheese, with holes in them. The holes represent things that prevent a particular precaution from working properly: broken equipment, failure to comply with procedures, etc. A hazard might make it past one precaution by slipping through one of these holes, but then get stopped by some other precaution. A mishap occurs when enough holes line up in a row for a hazard to get all of the way through. In most mishaps, there are three holes that lined up to make the mishap happen. For example, bad weather alone would probably not cause a mishap, nor would a hyrdaulic malfunction alone or a slightly low fuel load alone, but when you get all three together, shit gets out of hand and a mishap can happen. On a flight where nothing else goes wrong, consumer electronics alone are not going to cause a mishap, but on a flight where a couple of other things are going wrong, a single cell phone might be all it takes to tip the scales from "a really bad day for the pilots" to "mishap."

>Please stop the fear mongering on this.

I have personally experienced degradation of safety-critical systems in-flight due to EMI from on-board devices, including devices that are not designed to be transmitters. Nothing you carry onto a plane is going to cause it to explode without warning or go completely out of control (which are a couple of straw-men I have seen in this topic). What can, and does, happen, is that safety-critical avionics don't work right. During critical phases of flight (takeoff, departure, approach, and landing), this could be a contributor to a mishap. If your ILS goes haywire when you're in the middle of shooting an approach in actual IMC, you've got a big problem; likewise, if you can't talk on certain radio frequencies in the terminal area due to noise interference, you've got a problem.

>I put it into WiFi only mode about 10 minutes after takeoff when I can't get a signal anymore and just turn it back on when we are a half hour within landing.

If you have a GSM phone, then allow me to speak for every pilot you have ever been a passenger to: fuck you. No, really: fuck you. Put your GSM phone next to a cheap set of speakers: it will periodically make a noise (especially if you are sending/receiving calls or data, or if your phone is searching for the network). The same thing happens with most ILS receivers and with the ICS on many planes. So first, they'll have to use some other approach rather than ILS, which may not have been their primary plan. Then, imagine trying to run checklists and land a plane with that shit going off in your ears.

Even if you have a CDMA phone, there's a good chance you're interfering with something, making the lives of your pilots that much harder at a time when they can ill afford additional distractions.