Ah, the EU Air Passenger Rights - the bane of many a traveler's existence. As a detective, I've seen my fair share of flight disruptions, and let me tell you, these regulations can be a bit of a headache. But fear not, my dear detectives-in-training - I'm here to help you navigate the murky waters of delayed and cancelled flights.

First things first, let's talk about delayed flights. Under the EU Air Passenger Rights, if your flight is delayed by more than two hours, the airline is required to provide you with food and drinks, access to phone calls and emails, and accommodation if necessary. If your delay lasts for more than five hours, you also have the option to cancel your flight and receive a full refund.

Now, if your flight is canceled, the airline is required to offer you the choice between a full refund or rebooking on an alternative flight. If you choose to be rebooked, the airline must also provide you with food, drinks, and accommodation if necessary.

But wait, there's more! If your flight is overbooked and the airline asks you to give up your seat, you may be entitled to some pretty sweet compensation. The amount of compensation depends on the length of the delay and the distance of the flight, but in general, you could be looking at anywhere from €250 to €600.

Now, let's say you're sitting on the plane, ready to take off, when the airline suddenly realizes they've oversold the flight and asks you to give up your seat. In this case, you may be entitled to even more compensation. Depending on the circumstances, you could be looking at up to 400% of the ticket price, with a maximum of €600.

Of course, all of this is easier said than done - actually getting the airline to pay up can be a bit of a challenge. But don't worry, my dear detectives-in-training - if you find yourself in a situation where you're not getting the compensation you're entitled to, there are a few things you can do.

First, make sure you document everything - take note of the time, date, and circumstances of the disruption, and keep any receipts or other relevant documents. Then, contact the airline and explain your situation. If that doesn't work, you can file a complaint with the national aviation authority in the country where the disruption occurred.

And if all else fails, well, that's what lawyers are for, right? Just don't forget to call me as a witness - after all, as a detective, I have a keen eye for detail and a knack for getting to the bottom of things.

So there you have it, my dear detectives-in-training - the key EU Air Passenger Rights when it comes to delayed and cancelled flights, as well as oversold flights. Just remember to keep your cool, know your rights, and document everything, and you should be able to get the compensation you deserve. Happy travels!