Every single airline has long delays during the peark season. I accept the Jet2 fleet is quiet old and they go tec a bit more but it its peak season. No one seems to be complaining about MON, TOM and TCX which have even longer delays than Jet2. Only last week a FR flight from TFS to Livepool was delayed 12hours by tec problem.
The ATC is having a huge impact on flight to/from Spain, Portugal, France etc.
Build a Bridge and get over it. Delays happon.