The issue of ground handling is quite a specific example when considering the overall operational and financial performance of either airline. The point raised about under-utilisation of ground staff for Jet2 at certain times of the day is a fair one, but the same can still be said at various EasyJet stations where they have a more dedicated or exclusive ground handling provider. Ok they may not absord the cost directly, but their contractual terms will inevitably need to cover the cost of those demand variations. Either that or they receive a poorly resourced ground handling provision to which there's a whole host of problems.
Jet2 have a very clear focussed product which is European, mass market, good value package holidays to which they clearly recognise is a market that demands a certain level of service, above that of your traditional low-cost carriers where it's all about cost. The in-house ground handling provision is pivotal to that product/service offering that far outweighs any potential resourcing inefficiencies that may come around by the seasonal nature of Jet2's flying schedule. I for one, looking at the financial position alone and the fact that EasyJet, in my personal opinion, has a far less focussed product than many of it's obvious competitors, would disagree they are better placed to weather a downturn.