Recently re-formed with a new group of pilots after the previous line-up left to join the air arm of Qatar, the Croatian Air Force's Krila Oluje (Wings of Storm) aerobatic team flies six examples of the Pilatus PC-9M turboprop trainer. They hail from the 93rd Air Base at Zemunik, otherwise known as Zadar Airport. A first public performance was given in 2004, and the following year the team name was officially bestowed in recognition of the 10th anniversary of Operation 'Oluje' (Storm), a crucial and decisive battle in Croatia's fight for independence. Since 2009 a six-ship formation has been mounted. Seventeen examples of the Swiss-designed and built PC-9M are in Croatian service as advanced trainers, making it the air arm's most numerous type.