Cell phones on long bus and train rides are annoying enough - I can't imagine on a long flight. After paying all that money and then being accosted with other people's extraordinary dull conversations... grrr..
Which reminds me. If people talk to one another in a car, plane, etc. etc., their conversations are generally kept at a respectful level. So why do people yell into cell phones? Don't they have volume features? What's up with that??