Profits at Singapore Airlines (SIA) more than doubled to $804 million in the full year to March 31, on the back of lower fuel prices and one-off gains.

SIA pocketed an undisclosed amount when it agreed earlier in the year to release back to Airbus seven delivery slots for the A350-900 aircraft.

Its cargo arm, SIA Cargo also received a refund of $117 million for a fine paid in a prior year.

Group revenue came in at $15.2 billion, down 2.2 per cent from a year earlier, due in part to lower passenger revenue from the parent premium airline.

Total spending fell 4 per cent to $14.5 billion, mainly due to a 41.3 per cent drop in average jet fuel prices.

Group net profit for the final January-March quarter jumped more than four times to $224.7 million.

Revenue during the three months fell 4.4 per cent to $3.71 billion compared with the same quarter a year earlier while expenditure fell by 6.1 per cent to $3.6 billion.

With the exception of SIA Cargo, the parent carrier as well as subsidiaries SilkAir, Scoot, Tigerair and SIA Engineering all reported higher year-on-year operating profits.

SIA has proposed a final dividend of 35 cents per share, up from 17 cents a year earlier.

Full-year earnings per share rose to 69 cents from 31.4 cents a year earlier, while net asset value per share was $10.96 as at March 31, up from $10.66 a year earlier.

The airline faces a challenging operating environment in key markets, caused in part by weak economic activity and relatively rapid growth in capacity, SIA said in a statement yesterday. This has pushed fares and yields down.

SIA remains committed to its multi-pronged approach to address the structural changes in the industry, through its portfolio of airlines serving both full-service and budget airline segments, its multi-hub strategy, the pursuit of adjacent business opportunities and ongoing enhancement of premium products and services, the statement added.

Expansion plans are in the pipeline as SIA continues to face tough competition from rivals such as Emirates and Cathay Pacific in the long-haul premium market, and AirAsia and Jetstar in the budget space.

SIA will add three new destinations in the coming months with flights to Dusseldorf, Germany, as well as Canberra in Australia and Wellington in New Zealand.

Scoot will also grow its network with flights to the Indian cities of Chennai, Amritsar and Jaipur.

SIA aims to continue pursuing partnerships with like-minded airlines. For example, SIA and United Airlines are seeking approval from the US Department of Transportation to start codesharing from July.

This would allow the carriers to expand their networks by selling seats on each other's flights.