Is air shipping much more inefficient than truck shipping?

November 4, 2008 6:51 PM

How much jet fuel does it take to fly a 50lb box 100 miles vs. gasoline for driving the same box the same distance?

Assume the vehicles are going there anyway - what I want to know is the difference between flying an empty plane and flying one carrying the box, and the same question for a car/truck. Presumably the answer depends heavily on the type and efficiency of the plane and car, but approximate answers are fine. Are we talking roughly equivalent amounts of fuel, or an order of magnitude difference?

posted by Caviar to travel & transportation (7 comments total)

Have you already checked out the first result for a Google search on transport fuel efficiency, by any chance? It contains a good discussion of the issues, and a handy link to this graph from New Scientist that suggests that air freight is indeed about an order of magnitude less fuel-efficient than road.
posted by flabdablet at 7:24 PM on November 4, 2008

There is not enough information to answer that question. Using an ultralight plane to carry 50 ponds 100 miles is likely to use less fuel than using a Lincoln Navigator to do the same thing. Using a Jumbo Jet versus a Smart car will result in several orders of magnitude difference in the other direction. For all but the smallest vehicles, given your condition that they are going there anyway, taking a 50 pound box 100 miles will result in a negligible increase in fuel consumption. There are many other factors that come into play, such as landing fees at airports and the fact that ground transportation can go right where you want it whereas planes can only get your package as far as the nearest airport and then have to rely on ground transportation for the rest of the trip. This sort of calculation is done by businesses all of the time in order to minimize shipping costs; they take additional variables into account such as the shelf life/perishability of what is being shipped.
posted by TedW at 7:34 PM on November 4, 2008

Let's take some generally available fuel effienciency figures., and let's substitute an average person in place of your box.

From the linked data, average consumption for the air-travel industry in 1998 was about 5L of fuel per 100 passenger-kms. Worst-case scenario (driving alone) for a Toyota Prius is about 5L per 100km. If you load up the car, the impact on economy will be marginal, and your fuel consumption per passenger-km goes down drastically to about 1L per 100 passenger-kms.

Driving wins the efficiency war by far, and this is to be expected even with a basic understanding of physics, i.e. energy consumed = force x distance, and force to overcome aerodynamic drag goes up with the square of speed. The faster you go, the less efficient it is.
posted by randomstriker at 7:34 PM on November 4, 2008

A recent letter to the editor in Aviation Consumer (subscription required) noted the following:

I purchased my 1947 Cessna 140 in November 2005. I bought it to commute from my home in Algonquin, Ill., to the Chicago Executive Airport where I work as a corporate pilot. To drive to work is 50-60 minutes in Chicago traffic. My door-to-door commute using the 140 is 30 minutes, including a 12-minute flight.
...
My 140 has an O-200 engine.... In my commute I rarely get above 1800 feet, fly at about 100 KIAS and burn about 5.7 GPH. With the commute putting about .3 hrs each way on the tach, I burn 3.4 gallons at $4.59/gal as of Sept. 18, 2008. This comes out to $15.60 for my trip to work and back. My car gets 14 MPG, doing the drive I have to do, which translates to 3.71 gallons. With mogas currently at $4.35/gal., this comes out to $16.14 for the trip. So the price to fly my aircraft, in fuel, is cheaper than driving.

posted by exogenous at 9:55 PM on November 4, 2008

If they're already making the trip an additional 50 lbs of cargo is probably trivial relative to the fuel required to fly the jet or drive the car/truck/whatever.

A better way to approach this problem would be to see how much fuel a fully loaded jet and/or truck would use for such a trip and divide that by the total load to get a sort of pounds per gallon value.
posted by Kid Charlemagne at 10:07 PM on November 4, 2008

your question doesn't really work because a smaller plane (like a turboprop) doesn't use jet fuel and you wouldn't fly a larger jet for just one box (unless there is an organ donation in it, in which case I'd question your ethics for even asking about this). a car on the other hand can very well assumed to be traveling from point A to B just because of this one box. what I am saying is the plane becomes (in most cases) a method of public transportation as opposed to the car being an individual method of transportation and deserves to be thought of in just the way you would think of a bus. that is why I could walk up to southwest's cargo terminal in chicago midway and ship a pretty big and heavy box full of photography equipment to california for about $100. the fuel equation here for the airline of course is cost of fuel divided by (weight allocated per passenger plus sold cargo space, both of which are multiple present.)
posted by krautland at 11:33 PM on November 4, 2008

The story reported by exogenous is really cool. But that's a very old (and non-jet) plane with a tiny engine, compared to some honking car (or TRUCK-U-V) that gets 14 mpg. And he admits that he spends a ton of time sitting in terrible Chicago traffic. And still with all those things in the airplane's favor, it's basically a wash.

In general a car is more efficient.
posted by zpousman at 7:33 AM on November 5, 2008