Some information was taken from: http://www.amfor.org/clmt_chg/assumptions.html

The measurement of a single passenger's portion of a jet aircraft's contribution to climate change is subject to a great many variables based on the number of seats, the number of passengers, and the type and efficiency of the aircraft's engines, as well as the distance traveled. Shorter trips use considerably more miles-per-gallon-per-seat. The fuel efficiency is lower on shorter trips than on longer distance flights because take-off and landing use much more fuel than flying at altitude.

The Federal Aviation Administration estimates an average of 48 miles-per-gallon-per-seat. This figure takes into account non-revenue passenger miles such as those incurred while taxiing and in holding patterns.

Jet fuel and gasoline for cars create about the same amount CO2 emissions per gallon (around 20 lbs per gallon). Cars have fuel efficiencies anywhere between 10 mpg (a large SUV) to 60 mpg (a hybrid engine car like the Honda Insight). That means, if you travel alone in your SUV, you'll create more emissions than if you had taken an airplane. If you drive to your destination with your whole family in your small Honda, the emissions per person will be much lower than if your whole family had taken the plane.

This does not take into account the issue of marginal versus average carbon emissions. In other words, you could argue that the plane flies anyway, no matter if you are on it or not. Looked at it from this angle, adding one more person to the plane will only very marginally increase the amount of fuel the plane uses. From this view, it is always better to fly than to drive, because you'll avoid the emissions from your car.

Yet this argument is flawed. Planes only fly because there are people who want to get to places. During the Y2K scare around the turn of this century, hundreds of flights were canceled, because people chose not to fly. The consumer drives the supply.

The question of which is the more environmental choice — traveling by car or by plane — has no easy answer.

Even so, here are some simple suggestions for you to consider:

If you can avoid traveling for business by using video and phone conferencing, do it!

If you have the option of taking the train instead of the plane or car, take the train!

If you can choose between local vacations and vacations somewhere far away in the tropics, stay local!

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More Facts About Flying

Taken from Grist Magazine

350 million -- number of pounds of smog-producing chemicals (nitrogen oxides and volatile organic compounds) released by planes landing and taking off from U.S. airports in 1993

200 million to 600 million -- number of gallons of wastewater created each year from airplane deicing

219 -- number of volatile organic chemicals found in the air around Chicago's O'Hare Airport

5.6 -- number of miles a passenger could travel in an intercity bus using the same amount of energy it would take to move her one mile in a commercial jet

1.5 -- number of miles a passenger could travel in a commercial jet using the same amount of energy it would take to move her one mile in a single-occupancy car

30,000 -- number of flights completed in the U.S. each day

149 -- percentage increase in U.S. air travel (paying passenger miles) on major commercial airlines from 1979 to 1999

85 -- percentage expected increase in U.S. air travel from 1999 to 2020

10 -- approximate number of gallons of crude oil required to make one gallon of jet fuel

77 -- number of gallons of jet fuel needed for a person to travel from New York to Los Angeles on a commercial jet plane

13 -- percentage of total global, transportation-related carbon dioxide emissions released by airplanes

$40 billion -- amount of money appropriated by the U.S. Congress to construct and expand airports under the Air Expansion Act of 2000 (AIR-21)

71 -- percentage of members of the U.S. House of Representatives who received PAC money from the airline industry in 2000

6 million -- number of pounds of peanuts sold by Southern farmers to the airline industry each year, before nuts were banned on many flights

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Sources:

1 -- Natural Resources Defense Council, "Flying Off Course: Environmental Impacts of America's Airports," Oct 1996.

2 -- U.S. EPA, Office of Research and Development, "On-Site Recovery of Glycols from Airport Deicing Fluid Using Polymeric/Ceramic Composite Membranes," 15 Jul 1999.

3 -- City of Park Ridge, Ill., "Preliminary Study and Analysis of Toxic Air Pollutant Emissions from O'Hare International Airport and the Resulting Health Risks Created by These Toxic Emissions in Surrounding Residential Communities" (pdf), Aug 2000.

4, 5 -- Oak Ridge National Laboratory, Center for Transportation Analysis, Transportation Energy Data Book: Edition 20 (pdf), Nov 2000.

6 -- Kristin L. Falzone, "Airport Noise Pollution: Is There a Solution in Sight?" (pdf), Boston College Environmental Affairs Law Review, 1999.

7 -- U.S. Department of Transportation, Bureau of Transportation Statistics, Historical Air Traffic Statistics 1979 and 1999.

8 -- U.S. Department of Energy, Energy Information Agency, "2001 Annual Energy Outlook Supplementary Tables," Dec 2000.

9 -- American Petroleum Institute, "What A Barrel Of Crude Oil Makes."

10 -- New York is 2,462 miles from Los Angeles. There are 128,100 Btus of energy in one gallon of kerosene-type jet fuel, and it requires 3,999 Btus of energy to move one passenger one mile in a commercial jet. (Calculated from: Oak Ridge National Laboratory, Center for Transportation Analysis, Transportation Energy Data Book: Edition 20, Nov 2000.)

11 -- U.N. Intergovernmental Panel on Climate Change, "Aviation and the Global Atmosphere," Apr 1999.

12 -- Sharon Skolnick, "Airports' Poison Circles," Earth Island Journal, Winter 2000.

13 -- Center for Responsive Politics, Airlines: Top Recipients.

14 -- American Cynic, 07 Sep 1998.