sentences:  The highlight was a "Diamond 9" formation of Tornado GR4s and the appearance of a Canberra escorted by the Red Arrows.Historic aircraft of the Battle of Britain Memorial Flight, including Supermarine Spitfires and the Avro Lancaster perform flypasts throughout the year particularly on military anniversaries and occasions and as a mark of respect at funerals and memorial services.In many countries, flypasts, normally performed by the precision aerobatic team of a country's air force, are an integral part of Republic Day or National Day celebrations.