LCC's tend not to have a a mixed fleet, and this is part of their success. Realistically, it would be a Boeing order.
The thing about Airbus having a done deal, (allegedly, I know) is that Jet2 would use this in order to drive a better deal with Boeing. I do think they will go long haul, in the very near future, but instead, that will be with something like a 8-10yr old 767-300WL. Otherwise, I think
if there is any big order, the likelihood is lots of new 737NG's, and maybe a good few 737MAX's.
If rumour stands correct, hopefully we'll all know sooner, rather than later.
