You're entitled to get compensation if the flight arrives more than 3 hours late and it's the airline's fault - for example, if they didn't get enough bookings or there was a technical fault.
Can you claim compensation for delayed flight?
Does the delay have to be the airline's fault to claim via my travel insurance? Depending on your travel insurance policy, you could be able to claim compensation from your insurer when the delay isn't the airline's fault. Check your policy terms and conditions for what situations it'll cover.
Can I claim if my flight is delayed by 1 hour?
If it's the airlines fault, then you are eligible for a compensation. On the other hand, if the delay is caused by unforeseen extraordinary circumstances out of the airline's control, such as strikes, bad weather, technical faults, etc., then you can't claim a compensation.