The cancellation of 3,500 flights due to the Europe-wide air traffic shutdown slashed passenger figures of FlyNikis partner Air Berlin last month.The Berlin-based firm, which has a 49.9 per cent interest in Niki Laudas company, said today (Thurs) year on year passenger figures plummeted by 16.5 per cent to 2,065 million in April.Air Berlin said the cancellation of more than 3,500 flights following the eruption of Icelandic volcano Eyjafjallajökull was the main reason for the decline, adding that figures had soared in the first three months of this year compared to the same period in 2009.The firm Germanys second-biggest aviation company after Austrian Airlines (AUA) owner Lufthansa claimed customers were “insecure” about booking flights after the six-day aviation lockdown.Only 72.8 per cent of tickets on sale were booked last month, down by 3.7 per cent year on year.The number of Air Berlin passengers between January and April 2010 however rose by 3.1 per cent to 8.3 millions in comparison to the first four months of 2009.Air Berlin got better through “crisis year” 2009 than most competitors. The firm headed by Joachim Hunold suffered a 4.1 per cent drop in turnover year on year to 3.24 billion Euros. It had 28.5 million customers between January and December 2009.Rumours that Air Berlin is considering taking over FlyNiki have increased since it upped its stake in the partner airline by 25.9 per cent earlier this year.Lauda said of the deal which featured an option for a total takeover “I am and will remain major stakeholder and boss of my airline.”The three-time Formula One champion described the development as a “logical step”.”The even more intensive cooperation will make us more efficient and more attractive for customers,” he said.FlyNiki was founded in 2003 and has 450 staff today. It had 2.6 million passengers last year and Lauda said taking the three-million hurdle was his goal this year. The carrier recently started offering new connections between Vienna and Bucharest, Belgrade and Sofia.