If the flight is delayed:

• for two hours of more beyond it's scheduled time of departure in the case of flights of 1500km or less
• for 3 hours or more for flights of over 1,500 km within the EU, and for other flights between 1,500 and 3,500 km.
• for 4 hours or more for flights over 3,500 km outside the EU.

The airline is required to offer you food, drinks, phone calls and hotel accommodation (with transfers) if necessary.

For delays of 5 hours or more, the airline is required to provide alternative transport to your final destination and refund the corresponding amount of the service not used. 

For more information and details see European regulation 261/2004