This question already has an answer here:
My grandma is trying to request compensation under Regulation (EC) No 261/2004 from Air Transat, as her flight from England landed 4 hours past the scheduled arrival time in Canada. She recorded the time, but her telephone obviously isn't probative evidence.
But Air Transat refused, and countered:
The delay of your flight was under the 4-hour mark. Regulation EC261/2004 does not apply.
So how can she prove the delay of more than 4 hours, free of charge?