PARIS, March 8 (Reuters) – Air France-KLM said it would raise capacity on its long-haul flights by 0.8 percent this summer as it sees ''tentative signs of recovery.''

Airlines globally have slashed the number of seats on offer during the economic crisis in order to shore up the load factor, or the proportion of seats sold on each flight. The move was designed to stem the losses in average revenue yields per seat.

But there have been signs that airlines are starting to add seats on longer routes to prepare for a gradual economic upturn.

Air France-KLM said that despite the additions to long-haul capacity, it would trim its overall offering by 0.3 percent, reducing capacity on its medium-haul network by 4 percent.

''In the wake of 2009, an extremely difficult year for the world economy and air transport in particular, tentative signs of recovery – depending on the country -- have been perceived,'' the airline said in a statement.

The move came as global airline body IATA said capacity had started to return but at a ''very cautious rate,'' so that load factors had reached record levels in January.

''Travel and freight demand turning up strongly at the start of 2010 but (with) very large geographical differences,'' the Geneva-based body said in a report.

Air France, excluding KLM, will reduce the amount of seating available on summer services by 0.9 percent, driven by a 3.7 percent cut on medium-haul routes, the Franco-Dutch group said.

Air France and KLM merged in 2004 but continue to operate separate networks.

The world's airlines are set to post losses of $5.6 billion this year as they continue to struggle with the impact of the economic crisis on travel, according to IATA.