The NBC news site has the story on it today, Tue. Oct. 1. dated 9-27.
The example given is Delta who had 2 million passenger flights and had 27 reports of "POSSIBLE" interference from an electronic device.
"NONE OF THE REPORTED INSTANCES COULD BE VERIFIED."

The real danger for an airline is not some passenger on a cell phone or I pad; rather it is financial. Delta , like others has already had one bankruptcy. I had some bonds issued to pay for their terminal at DFW which they defaulted on.