I find the use of the word "Chav" derogatory, however its not hard to imagine the lower middle classes jumping on the word, after all we all like to make fun of people somewhat less fortunate than ourselves don't we?
As for the "legacy of cheap flights" why is it that some people equate lower socio-economic class with trouble? What you are trying to say is, to cut a boring explanation short, is that the poorer you are the less well behaved you are likely to be.
The word b*ll!!!!! comes to mind.