As well as having 550,000 fewer seats because of the 3,500 cancelled flights, the airline had also suffered from a drop in bookings because passengers were unsure whether they'd be able to fly, the airline announced.
The gradual resumption of flights across Europe led to prolonged uncertainty among passengers, the airline said, meaning they simply didn't purchase flights, which cut the airline's revenues as well as its “capacity utilisation” – the number of seats it fills.
Air Berlin flew about 2.1 million passengers in April – some 16.5 percent fewer than in April 2009. The capacity utilisation of its April flights dropped 3.7 percentage points to 72.6 percent compared with the previous year.
Aviation authorities closed much of Europe's airspace for five days in April because of a dangerous layer of ash from the Icelandic volcano Eyjafjallajökull that drifted right across the continent. According to a report on Wednesday, the volcano was still emitting ash, though not in the quantities it did at the peak trouble period.
The flight bans were finally lifted on April 21. German Transport Minister Peter Ramsauer hosted a meeting for airlines and aviation officials in Berlin later in the month to review ways to handle future problems with volcanic ash.