The article is about whether cell phones and electronic devices are a threat to avionics. It describes a study where an antenna and spectrum analyzer was flown as overhead baggage on 37 domestic flights. Here's a brief summary from a Honolulu Advertiser article:
The researchers concluded something else surprising by extrapolating data from tests they conducted in late 2003 on 37 flights in the eastern United States: One to four cell-phone calls are typically being made aboard every airline flight in the country, despite the fact that the calls are illegal and that flight crews tell passengers not to do it.
I also found it particularly interesting that NASA issued a technical memorandum about how a certain model of Samsung phones "caused their GPS receivers to lose satellite lock" when used by general aviation pilots. The actual technical memorandum is very readable.