LNIDA
as you say all airlines change schedules. Jet2s passenger operations serve the holiday market, and reading sites such as Tripadvisor I see people regularly booking holidays 12 to 18 months ahead, either for special occasions or budgeting reasons. Also as Leeds Spotter says accommodation fills up at some times of year
My schedule change story with Jet2 last year involves 2 returns, flight only, from GLA to LPA.
The trip in October the return flight was moved back by 10 minutes, hardly worth telling me about I thought.
The trip at Christmas was another matter. Booked at the beginning of May with Saturday flights out and back. Email received 9 July informing of a 24 hour change of times of both flights so that travel was on Sunday. In fact all flights from GLA to LPA from Nov 8 were changed to Sundays. Luckily my accommodation had space to let me modify my booking and change at no cost, parking was another matter.
I'd certainly fly with Jet2 again. Friendly cabin crew and no delays. Don't know about others but I find the new style no recline seats on a 738 more comfortable and give me more leg room than the old style seating on charter 752s.