Airline insurers have endured the most expensive claims year in recent history, with figures from global broker Aon revealing total claims of about $US2.3 billion ($2.5 billion).

While the total cost of claims in 2009 was well above the average $US1.8 billion ($1.9 billion) in costs incurred between 1998 and 2008, with hull and liability premiums rising 20% during the year, the actual number of events was less than the long-term average.

The figures are revealed in a new Aon report on the outlook for the airline insurance market, which says the claims figure is likely to be the highest in aviation history.

The report notes 58 major losses during the year, compared to a long-term average of 68. Total fatalities for the year were 423, compared to an average of 635.

Major catastrophes included Air France flight 447, which crashed into the Atlantic Ocean en route to Paris from Rio de Janeiro on June 1, killing 228.

Aon says 2009 was the third consecutive year of losses for airline underwriters and while premiums are expected to rise further, improving economic conditions should temper more extreme increases.

“The potential for a slower rate of price increases in the airline insurance market will be welcome news for an industry that has endured significant challenges during 2009,” Aon said in the report.