Originally Posted by
filtersweep
Since when? Efficiency can also be measured in pure cost, energy expended, etc... the only time "time" becomes significant is if it factors on price or customer satisfaction.
One thing that sucks about ships is that unlike planes, they cannot float over the weather. This makes travel a bit more unpredictable.
But you're talking about physical or mechanical efficiency, which is only one part of the equation for commercial cargo. In this sense, ships and trains are far more efficient, in terms of fuel consumed times distance times weight. But time is money, and the longer the shipment is in transit, the less money the importer makes. At some point trucks become more efficient, then air freight.
Same with business travel. If a salesman is making $200 a day, he can drive a car. If his regional manager is making $500, it's more efficient to fly him on a commercial airline and get him a rental car at the airport. If the CEO's salary is $100,000 a day, it suddenly makes sense to fly him by corporate jet with a helicopter waiting at the airport.