JC Decaux, one of the world's largest outdoor advertising groups, yesterday said a marked upturn in business at its airport and railway station operations had helped generate a 6.2% increase in organic revenues.

Sales at JC Decaux's transport division had been rising throughout 2004, ending up 12% at €313m (£223m). In the final three months of the year the division grew by 17%.

Its fortunes have largely tracked weaknesses in airport passenger traffic in recent years. In a statement, JC Decaux said: "Following two difficult years, 2004 is showing strong signs of a recovery." The group's 6.2% organic revenue growth outstripped an internal target of 5% as well as the industry average for the year of 6%. Total sales for 2004 reached €1.63bn, up 5.7%.

Jean-Charles Decaux, chairman and joint chief executive, struck a note of caution, reminding investors that revenue gains from airports tended to come at lower margins.

However, sales gains were not isolated to the transport division. Revenues from street furniture advertisements, such as scrolling publicity on bus shelters and toilet cubicles, grew steadily throughout 2004 - up 5.7% at €885m.

JC Decaux said particularly strong performances were recorded in the UK and Portugal, with the latter benefiting from publicity around the Euro 2004 football tournament.

The group's billboard business also showed growth - up 4.4% at €434m after stripping out currency fluctuations, acquisitions and divestments.

Mr Decaux said: "2004 was a year of strong organic growth across all of our activities, with an acceleration in the second half, allowing us to outperform the advertising market." The group will publish full results for 2004 and comment on current trading next month.

Bullish industry insiders have suggested that outdoor advertising could reach 10% of all advertising spending this year.