Dr Alf raises an important point, because airline CEOs and their major shareholders would not sit with anyone like that for one second.
Passengers who are grossly obese should be charged for two seats whilst the smelly, troublesome, drunk and flu ridden should not be allowed to fly on normal commercial flights.
The airlines owe a duty of care to the ordinary travelling public, who queue in airports and have to put up with these things.
Apart from the airlines, people need to learn manners again, even if that means applying fast-track ASBOs and fines on people and their errant offspring and charging them a lot more before they can travel with the rest of us.