Jet2 are most likely using other airlines as they don't have enough aircraft and resources in the current fleet.
Pilot and Cabin crew recruitment is very heavy at the moment. Jet2 will be hiring an additional 55 - 60 cabin crew for S08 in NCL alone.
(Applications may be sent in now by the way!)
Pilot and Engineering recruitment is high too, with adverts on the website and in Flight International (02-08 Oct).
The biggest problem is getting hold of reasonably priced and well maintained aircraft. The 2nd hand price for a half decent 757 has gone trough the roof since UPS announced that it wants to buy and convert around 100 into a Cargo fit.
Not sure on the availabilty of 767's at the moment though ............
