The Europeans are in the same position as the Americans when it comes to the rules on compensation when flights are cancelled or passengers are refused boarding. As from 2004, there have been a unified set of rules to ensure that everyone gets the same treatment no matter which country they are flying in or to - for the record, comparable rules apply to train services and other forms of public transport although the substance of the rules varies, e.g. the detail of rights on trains are not the same as those applying to maritime and river transport. This article only addresses the rights available to citizens of an EU Member State. Even if an American is a passenger on a European flight in Europe, none of these rights apply. The only remedies come under international treaties. However, Americans in Europe do get an indirect benefit.
The first and most obvious consumer right is to receive comprehensive information in a timely manner. If a problem arises hours before boarding is due, airlines should notify passengers by sms, Facebook or some other means to minimize inconvenience and avoid travel to the airport. Once you have arrived and presented yourself for boarding within the time limit, you're entitled to compensation if the plane is overbooked and you cannot get a seat, even if you have cheap air tickets. The current practice is as follows. The airline first calls for volunteers who are prepared to give up their seats for an agreed amount of compensation. If no one volunteers, you must be offered a full refund or re-routing to your destination at the earliest possible time. For these purposes, a full refund includes the cost of flying you home if the purpose of your journey is now frustrated, e.g. you were flying to attend a friend's wedding and you will miss it. If you choose a refund or re-routing, compensation must also be paid. This is up to 600 Euro depending on the distance you were due to fly. If your seat is upgraded, you cannot be asked to pay a higher ticket price. If you agree to accept a downgrade, the airline must refund the difference in seat price even if you had cheap air tickets.