As most people know, cell phones are a big no-no during landing and takeoff. What most people don't know, however, is why.

The FAA says cell phones to be "radio transmitting devices" that could possibly disrupt the avionics of the plane. Interesting that they don't call pacemakers transmitting devices, though. In 2007, the ABC news show 20/20, along with veteran airline pilot John Nance, conducted research disputing the FAA's stand. Nance stated: "There's little reason to worry about cell phones interfering with an airplane's navigational equipment," and went on to say airliners electronic systems are "heavily shielded" against stray radio or electronic signals.

Opponents claim that while one or two devices may not break an avionic shield, a lot of them could interfere with communication between the pilot and ground control--communication that's especially critical during takeoff and landing. In the case of emergency, jammed communication with the tower could cause disaster.

So who's right?

Well, according to the MythBusters, it's generally safe to use a cell on a plane. They did some similar debunking. However, because there are so many different types of devices and ways the phones can malfunction, there's no way to test every single cell phone that's been made. 20/20 determined that the primary reason for the ban on cell phone is that neither the FAA or the FCC are willing to spend the money to perform conclusive safety tests. Mmmm, okay.

According to Wiki: "Virtually every pilot headset sold on the market today comes with a cell phone adapter so that the pilot can use his cell phone." While airlines claim that pilots never use their cell phones mid-flight, we're not completely convinced.

pilotphoneat_Other research indicates that AT&T suggested in-flight mobile phone restrictions should remain in place in the interest of reducing the nuisance to other passengers caused by in-flight cell phone conversations "“ again, not at all a safety issue.

Some skeptics have posited the idea that the cell phone ban exists to spur use of the airline's built-in phones, phones that charge a significant fee. There's also some research stating that mobile phones are not all that reliable in the air in the first place, since they're not designed to switch from cell tower to cell tower at the speed of an airplane.

Interestingly enough, the FAA gives the pilot of each aircraft the right to grant the use of cell phones mid-flight. So hey, maybe next time you should buy your pilot a cup of coffee at the terminal. Who knows, they might grant your cell phone an exception.