Its the shortage of flights that is the problem, too many passengers and not enough flights - which means they can increase the price and people still pay it rather than travelling to Manchester.
Sometimes if its a package holiday it is dearer because the package company doesn't have the same discount negotiated for the different airports/airlines or price is based on their own chartered flight, if they are purchasing single seats at another airport it is going to be dearer.
In a time of universal deceit - telling the truth is a revolutionary act. George Orwell
When the debate is lost, slander becomes the tool of the loser. Socrates