The replacement of the 757 will always be a tricky one. Despite its age, nothing we have yet outperforms in terms of range in its class. Inevitably, when they do retire, the question is, will Jet2 even seek for a replacement for it? From what I can see, 30 -800 orders suggests that the future plan is to start standardising (and modernising) the fleet, which of course can reduce costs. The 737-800 suits the vast majority of Jet2's ops, albeit excluding the winter breaks to New York - which are just ad-hoc and not solid destinations.
However, should a decision come to replacing the 757s with something other than the 738, The viable options I see are go smaller; 739 or the a321, or go bigger; the 767.
The argument for the 767 is that they're still in production, share a common TR with the 757, have a vast network of spares, and are able to cover the ad-hocs like EWR in the winter, whilst during the summer, could easily serve full-load factors of bucket and spades to the likes of PMI, ALC or TFS. Should they decide to expand this way, I'd imagine an order of around 2-4, to make up a small sub fleet on the side (most likely based out of MAN).
When it comes down to the 739 vs the a321, in terms of performance they are
very similar. Take a look here:
http://planes.axlegeeks.com/compare/231-270/Airbus-A321-vs-Boeing-737-900ER
Now we all know LS negotiated significant discounts off the list prices for their NG order. The fact the 739, at list price is $28,700,000 cheaper than the airbus, suggests to me that the 739 is more likely, and given the substantial order with Boeing already, the company is a lot more likely to obtain significant discounts off the list price, than it would be with Airbus. Going this way would also maintain fleet commonality, which is of course very important in terms of keeping costs low.
Personally, I think that they'll just expand, standardising the fleet with the -800. I am certainly not ruling out the possibility of the a321, but think rather that the 739 is more likely. The 767, not so likely, but I think it would be a perfect fit into the LS ops, opening the
possibility of more far flung Jet2holidays destinations in the future.
