Singapore's assets: SIA Cargo's chief says freight carriers are selling themselves short in a world of expedited supply chains.(Pacific)(Singapore Airlines Cargo)

Hwang Teng Aun has no illusions about one of the most important sources of value within Singapore Airlines Cargo. The president of the Asian air freight giant looks past all the talk of wider issues pulling and pushing at the world's cargo market to what he sees as the foundation of SIA Cargo, the "beautiful assets" of aircraft that fly one of the most significant networks in the logistics business.

It's the aircraft that chart SIA Cargo's path in the world of global trade, he notes, and the aircraft that also are at the heart of the some of the carrier's toughest questions in the volatile market.

"We are giving away our perishable assets," Hwang says. "Other businesses don't do that. The shipping business doesn't do that. We are the only guys who do that."

To Hwang, the question of return on investment is one of the toughest puzzles facing the air freight industry today. It's a question built on the straightforward common sense that falls …