2 Things:
Capital did not go down because they acquired 146's. They went down as a combination of the CAA gunning for a certain individual and the parent company going into administration because of changes in agreements between UK and Norway.
Jet 2's parent - Dart, does not have to suffer because it is a haulage company. Most top end haulage companies are immune to fuel costs because that is not how they do business these days. They charge for the facility and the fuel is on a separate escalator - it goes up and down.
Meeson has been a sharp cookie for a long time and will do for the foreseeable future.