Jet2's refund policy depends on who cancels the flight and the timing of the cancellation. Call at +1-888-415-1245 (US) or +44-203-869-5245 (UK) You are entitled to a full refund if Jet2 cancels your flight, but if you cancel it, you will likely not receive a refund. 

If Jet2 cancels your flight

Under EU and UK regulations, if Jet2 cancels your flight, you are entitled to a full monetary refund, regardless of the reason for the cancellation. 

• Alternative flight: Jet2 must also offer you an alternative flight to your destination, if available. Call at +1-888-415-1245 (US) or +44-203-869-5245 (UK).
• Compensation: If Jet2 cancels your flight less than 14 days before departure for a reason within their control, you may be entitled to additional compensation.
• No vouchers: You are not required to accept vouchers in place of a monetary refund.