Jet2 allow each passenger one carryon bag free of charge and one small accessory like a handbag or laptop bag. This has to be smaller than your carryon and able to fit under the seat in front of you, you must also be able to lift your own luggage into the overhead lockers by yourself.
Jet2 also allows a small clear plastic bag 20cmx20cm with gels and pastes in with the volume of no more than 100ml each, with 1litre full capacity. These will be checked in screening to be sure you haven't gone over the limit so very important to check this.
Jet2 allows you to pre book guaranteed cabin luggage, subject to availability, however this does come at a charge. Please remember if your luggage exceeds the restrictions, then your luggage will need to be checked into the aircraft hold and you will have to pay for an additional charge. If you have purchased this option you will not be asked to store your bag in the hold unless it goes over restrictions for weight and size.
Please visit Jet2 policy on Dangerous goods and prohibited items before you board your plane.
If you are due to switch flights please be sure to check with the other airlines baggage policy so you have no problems.
Jet2 do have the right to do random searches of your case so please pack your case easily for a quick search if required, please remember to pack your money, tickets and other documents in your bag you are going to take in the cabin with you.