As airlines slap travelers with separate charges ranging frombaggage fees to fees for switching to a better seat or boarding theplane early, Concur has tweaked its expense management software tohelp companies track those costs.

Over the last six months, 2.3% of Concur's customers' overallspending with airlines has consisted of such ancillary fees, saysEllen Trotochaud, senior director of analytics and travel supplierrelations at Concur. Just two years ago, she says, the only airlinefees companies usually encountered were those for changing tickets,which were buried in the cost of the ticket.

The International Air Transport Association says airlines willtake in about $58 billion in ancillary fees this year, Trotochaudnotes. “Just baggage alone is targeted at about $4 billion. That'sa lot of spend.”