My flight was delayed by 9 hours and once we set off was ok although the plane did appear to be old worn and shabby inside. The delay was due to a generator failure on the previous flight when the plane had to make an unscheduled landing in Naples. On the flight back from Kos (which we were not on the plane), they had to make another unscheduled landing back in Kos due to a generator problem.
Avoid school holidays: Many cheap airlines take advantage of school holidays to increase their prices, as they expect to have a larger number of passengers than usual. During these periods a late booking (1 week before departure) may result in your paying more than the price of a ticket with a regular airline. It is therefore advisable to avoid these periods, if possible.