Historically, Jet2 took its pilots from a variety of sources, including OAA, but also PAT (where I went), plus the military etc and other TP carriers, such as Eastern. It has meant the airline has a very good mix of experience, even in the ranks of its F/Os, ranging from the inexperienced to those waiting for command upgrades.
At the moment, although the airline has been interviewing, a decision was made to only take Type Rated individuals for this coming season. This has left many of those who work in OPS and other airline positions, who already have their ATPL(F) bitterly disappointed, particularly for those who have already attended (and paid) for the JOC/Advanced Handling course at CTC.
I hope those who have shown remarkable commitment to the airline in non-flying positions are given their chance prior to others external to the company.