Alcoa kicked off the earnings season last night by reporting a larger first-quarter profit than analysts expected, helped by strong demand for aluminium used to make planes and cars.

The company still sees demand for aluminium growing by 7% in 2013, with gains cutting across many industries.

Alcoa is the first company in the Dow Jones industrial average to report first-quarter results.

Because its products wind up in so many things, from cars and buildings to drink cans, investors study Alcoa's results for hints about earnings at companies in other industries.

Alcoa said last night that its net income in the first quarter was $149m, or 13 cents per share, compared with $94m, or 9 cents per share, a year earlier.

But revenues fell to $5.83 billion from $6.01 billion a year earlier and was below the $5.91 billion that analysts predicted. Alcoa blamed lower aluminium prices and curtailed production in its European primary metals business.

Over the past decade, Alcoa has shifted more of its business away from mining and refining and into the production of parts for industry.

The company is benefiting as airplanes and cars get lighter for better fuel efficiency by using more aluminium parts. Airlines have been ordering new planes to reduce their spending on fuel, the largest cost for many of them.

That trend should continue for several years, making aerospace a growing aluminium market, chairman and chief executive Klaus Kleinfeld said in a conference call with analysts.

US car sales are booming, too, as customers who put off purchases during the recession trade in their ageing vehicles. In March, sales hit 1.45 million vehicles, the highest total since August 2007.

Alcoa believes that government fuel standards and customer demand for better mileage will push car makers to use more lighter materials like aluminium.

Some drivers think heavy vehicles are safer in a crash, but Kleinfeld argued that lighter cars can brake to a stop faster, potentially avoiding accidents.

Sales of aluminium for non-residential construction is finally recovering in North America and will grow much faster in China, Kleinfeld said.