What are your rights as a consumer for airlines that cancel flights?
If the airline blames the inclement weather, check if flights are taking off and when other airlines are flying. This shows good proof that weather is fine. It still may be considered an extraordinary circumstance and compensation might not payable in accordance with article 5(3) of 261/2004, however you are still allowed to have the case looked at
By defaults airlines will try and cancel this claim with reasons like
These are just default letters and actually have sometimes no real bearing on your complaint
Over Booking ( Bumping )
If you are bumped off a flight due to over booking of an airline, then you should be entitled to compensation. Usually airlines will tell you at the Check In Desk or Gate when this is happening and offer people vouchers/points or money for them to voluntarily be bumped
What am I entitled to?
It really depends on your distance of your flight and the length of delay. The citizens advice website has more info on this
How do I complain to a higher airline ombudsman authority?
Let Aviation ADR adjudicate. If they rule in your favour and you accept it is binding on the airline. Aviation ADR is free of cost and comes at no risk. If they rule against you, you could always proceed to the County Court if you could be bothered