So what's the problem with asking them to stop? Who's to say I wouldn't be annoyed every time someone looks at me on the airplane? Am I allowed to utilize the powers of the government in order to get you to stop looking at me? It's really REALLY dangerous to start passing laws based on annoyance, that might be even worse than legislating morality (there is a good episode of Penn & Teller Bullsh*t on the subject, btw). I don't like children on airplanes because they cry all the time, I say we ban them all together. Do you see where this is going?
So perhaps our civil liberties have been banned on airplanes?! In the end, the airplane is private property and flight attendants being the representatives of the owner can have the final say, since the airline wants the customers to come back. If one person is annoying 10 others, they want to stop that person to assure the 10 other people come back, not because some law says the attendant MUST do it. The flight attendants are not government employees, they are people acting in their employer's best interests. Do we really need to make LAWS telling people how to act in every situation in society? Why limit it to planes? Why not restaurants, buses, elevators, hallways... anywhere someone might get annoyed.
Oh my, we really should pass a law right away dictating exactly how everyone should act! This problem it out of control! My point is that a little consideration for others, and being willing to tell someone if you're having a problem (or just putting on some headphones and listening to music), can take care of it. Do we really need the government to babysit us?