Energy Use in Flying: Overview & Tips

Jan 12, 2012 | Air Travel

Flying uses a lot of energy.  Planes are fuel-efficient, but trips are long.  Read on to learn more.

THE BIG PICTURE

It may seem odd, but think of planes as energy efficient cars.  Once you average the fuel used per flight across all the passengers, planes have an average of 60 miles per gallon (mpg) per passenger on shorter domestic flights and an average of 52 mpg per passenger on international flights. (These are 2010 data, reflecting actual flights, miles flown and number of passengers per flight.)

In practice, airplane trips are much longer than car trips. So energy use per flight is fairly large.  Eliminating one flight per year reduces energy use by the same amount as dozens and dozens of car trips.

If you fly,  annual energy use from flights is likely to be 5 - 30% of your annual energy budget.  But airline travel as a whole is only 2 - 3% of our nation's energy use, as 60% of Americans don't fly each year.

SURPRISING FACTS

#1 Cars and planes emit about 20 lbs of CO2e per gallon.

The two modes of transportation both burn fuel from petroleum, and despite significant differences in technology, per gallon emissions are about the same.
 

#2 Long, crowded flights are the most energy efficient.

Long international flights use larger aircraft, which are more energy efficient.  When the flight is fully booked, less fuel is used per individual passenger.  So, to have lowest energy use per passenger mile, choose those crowded, long flights (and don't complain-too much!)

ENERGY SAVING TIPS

Skip the trip. The best way to save on your energy footprint is to reduce the number of flights you take each year. Consider video chats or teleconferences.

Drive instead. If you have a few passengers, it may save energy to drive.  For example,  a 400 mile trip in a car that gets 20 miles per gallon requires 20 gallons of gasoline.  Flying this length requires 7 gallons per seat.  So if there are three passengers a total of 21 gallons can be attributed to flying and one gallon can be saved by driving.  If there are four passengers 28 gallons can be attributed to flying and 9 gallons can be saved by driving.   To do these calculations yourself, simply compare the total gallons from flying the trip length for all passengers  with the total gallons needed to drive the car the same distance. 

FOR MORE INFORMATION

See the details on our calculations for energy use in flying here.

Check out our blog post critiquing "green airline" claims.

Keywords: flying, carbon emissions from flights, saving energy, airline emissions, airline energy use.