What airlines have an audio channel where you can listen to Air Traffic Control communications during the flight? Do any airlines allow you to bring a scanner or aviation radio aboard to listen yourself?
The only one I'm aware of is United Airlines, on Channel 9; this appears to be disappearing rapidly as Continental did not have it.
Radios are never permitted in flight.
However, there are websites with live ATC feeds so if the flight had WiFi you might be able to listen through a computer. I have used the iOS app version of LiveATC to listen to traffic control using inflight wifi; this only works over 10,000 feet when the wifi is on and you have to know the frequency that your cockpit crew happens to be on.