Energy intensity of passenger air travel and freight
3.7 A comparison of the average fuel intensity of airlines
3.7.1 A closer look at the American air carriers
This section takes a closer look at the specific fuel consumption of the American air carriers. The data material shown here covers the overall traffic performance of all the US carriers in the years 1982 and 1999. These data are not biased by the fuel consumption of all-cargo carriers that was included in the overall data shown in Figures 3.1 and 3.3. However, the data still include the fuel consumption that is attributable to belly-hold freight in passenger aircraft. The data describes the fuel consumption per ASK on domestic routes (Table 3.5) and on routes to Latin America (Table 3.6) as well as on Atlantic (Table 3.7) and Pacific routes (Table 3.8). Furthermore, the passenger load factors are available for each airline in 1999. These data exemplify the differences in the specific fuel consumption among the various airlines in the different markets.
Figures 3.9 and 3.10 exemplify the variations in the specific fuel consumption of a number of US air carriers.
Figure 3.9: Illustration of the specific fuel consumption per ASK and RPK of American air carriers in domestic operations in 1999
Source: [DOT 2001]
Figure 3.9 shows the average yearly specific fuel consumption per ASK and per RPK of US air carriers on domestic routes in 1999. The specific consumption varies between 27g and 64g per ASK and between 36g and 102g per RPK, if excluding a single carrier that uses some 74g per ASK and 160g per RPK. Among the Major US airlines that performed around 90% of the domestic revenue passenger kilometres in the United States in 1999 the specific consumption ranges between 30-37g per ASK and 44-53g
0 30 60 90 120 150
0 500 1000 1500 2000 2500 3000
Average stage distance
Specific fuel consumption [g]
Fuel per RPK Fuel per ASK
Average per RPK Average per ASK
per RPK. The large regional carriers, such as American Eagle and Continental Express, typically use around 50% more fuel per ASK and per RPK than the Major air carriers do. The overall average specific fuel consumption on domestic routes is around 35g per ASK and 50g per RPK. In 1982 the average specific consumption per ASK was about 43g suggesting a reduction of approximately 8g per ASK in the period or about 19%.
Figure 3.10: Specific fuel consumption of US air carriers on Domestic, Atlantic, Pacific and Latin America routes in 1982 and 1999
Source: [DOT 2001]
Figure 3.10 illustrates the specific fuel consumption per ASK on Domestic, Atlantic and Pacific routes and on routes to Latin America in 1982 and 1999. On routes to Latin America, the average specific fuel consumption is about 32g, representing a reduction of some 7g per ASK or about 17% as compared to 1982. In the Atlantic traffic the average specific fuel consumption is about 33g per ASK, representing a reduction of some 5g or some 13% in the period since 1982. In the Pacific traffic the specific consumption is about 38g per ASK, representing a reduction of 4g or some 10% in the period since 1982. That is, the fuel intensity per ASK is lowest on routes to Latin America and on Atlantic routes and a little higher on domestic routes and highest on pacific routes. These patterns fit with the trends illustrated in Figures 3.4 and 3.7 with the highest specific fuel consumption on short-haul routes and slightly higher fuel consumption on long haul than on medium-haul. The reductions since 1982 have been greater in the medium haul segments than in the long-haul segments.
20 30 40 50 60 70
0 2000 4000 6000 8000 10000 12000
Average stage distance [km]
Specific fuel consumption per ASK [g] Domestic 1982
Domestic 1999 Atlantic 1982 Atlantic 1999 Pacific 1982 Pacific 1999 Latin America 1982 Latin America 1999
1999 1982
g/ASK g/RPK Avr.
dist [km]
% of ASKs
g/ASK Avr.
dist [km]
% of ASKs
Domestic Domestic
United Air Lines 33 47 1486 12,2 United Air Lines 39 1387 14,2
Delta Air Lines 36 50 1166 11,9 American Airlines 43 1417 10,2
American Airlines 34 50 1672 11,7 Delta Air Lines 44 868 10,1
Northwest Airlines 37 53 1182 6,4 Eastern Air Lines 44 917 9,5
Continental Airlines 35 48 1537 5,7 Trans World Airlines 43 1241 5,9
Southwest Airlines 33 48 747 5,6 Republic Airlines 48 546 3,8
US Airways, Inc 37 53 927 5,6 Northwest Airlines 47 985 3,5
Trans World Airlines 37 50 1241 3,3 Continental Airlines 43 1112 3,3
America West Airlines 30 44 1384 2,7 Western Air Lines 40 1008 3,2
Alaska Airlines 33 49 1199 1,7 Pan Am. World Airw. 42 1605 3,0
American Trans Air 32 41 1405 1,2 US Airways, Inc 52 549 2,5
Hawaiian Airlines 37 49 1741 0,6 Piedmont Aviation 49 511 1,6
Airtran / Frontier (Old) 40 - 843 0,6 Airtran / Frontier (Old) 42 626 1,3
American Eagle/Simm 44 72 368 0,5 Southwest Airlines 43 477 1,1
Continental Express 47 76 469 0,4 Pacific Southwest Airl. 39 565 1,1
Frontier Airl. (New) 30 50 1307 0,4 Ozark Air Lines 46 589 0,9
Sun Country Airl. 33 50 1686 0,4 Texas Intl. Airlines 43 736 0,7
Spirit Air Lines 36 48 1401 0,3 Braniff 44 636 0,7
Midwest Express Airl. 50 76 1239 0,3 Air California 40 566 0,6
Tower Air 27 36 2737 0,3 People Express Airl. 36 860 0,6
Reno Air 38 61 796 0,3 Alaska Airlines 52 884 0,5
Mesaba Aviation 54 95 348 0,3 Wien Air Alaska 57 332 0,3
Atlantic Southeast Airl 47 80 440 0,3 Midway Airlines (Old) 46 714 0,3
Horizon Air 54 87 365 0,2 New York Air 37 531 0,3
Air Wisconsin 39 59 502 0,2 Capitol Intl. Airways 31 2593 0,2
Midway Airlines (New) 57 86 760 0,2 Hawaiian Airlines 50 188 0,2
Champion Air 40 - 1877 0,2 TranStar Airline 38 477 0,1
Totals 35 50 1287 74,1 Totals 43 1102 80,4
Table 3.5: The fuel consumption per ASK of the American air carriers in 1982 and per ASK and RPK in 1999 in domestic operations39
Source: [DOT 2001].
1999 1982
g/ASK Avr.
dist [km]
% of ASKs
g/ASK
Avr. dist [km] % of
ASKs
Latin America Latin America
American Airlines 33 2280 2,7 Pan Am. World Airways 41 2539 1,4
Continental Airlines 37 2225 1,0 Eastern Air Lines 36 1158 1,0
United Air Lines 29 4192 1,0 American Airlines 38 1605 0,8
Delta Air Lines 28 2454 0,4 Western Air Lines 36 2230 0,3
Alaska Airlines 31 1830 0,2 Braniff 44 1401 0,2
Delta Air Lines 37 1535 0,2
Totals 32 2589 5,41 Totals 39 1856 3,9
Table 3.6: The fuel consumption per ASK of the American air carriers in 1982 and 1999 in traffic to Latin America40Source: [DOT 2001].
39 Note that only those airlines performing more than 0,14% of the total ASKs (performed by all American airlines on all routes in 1999) within each segment, that is Domestic, Atlantic, Pacific and Latin America are shown in tables 3.5-3.8. This choice has been taken to limit the use of space for the Tables.
40 See footnote above.
1999 1982
g/ASK Avr.
dist [km]
% of ASKs
g/ASK
Avr. dist
[km] % of ASKs
Atlantic Atlantic
Delta Air Lines 35 6618 2,4 Pan Am. World Airways 41 2401 4,1
United Air Lines 29 6394 2,3 Trans World Airlines 35 5177 3,4
American Airlines 34 6528 2,1 Northwest Airlines 41 3592 0,5
Continental Airlines 38 6117 1,5 Delta Air Lines 36 7087 0,3
Northwest Airlines 36 6359 1,3 American Airlines 31 7616 0,2
US Airways, Inc 22 6236 0,6 Capitol Intl. Airways 30 4979 0,1
Trans World Airlines 30 5903 0,5
Tower Air 40 5679 0,4
American Trans Air 29 3086 0,3
World Airways 28 4327 0,3
Totals 33 6236 11,8 Totals 38 3882 8,5
Table 3.7: The fuel consumption per ASK of the American air carriers in 1982 and 1999 in Atlantic traffic41
Source: [DOT 2001].
1999 1982
g/ASK Avr.
dist [km]
% of ASKs
g/ASK
Avr. dist
[km] % of ASKs
Pacific Pacific
United Air Lines 36 7257 3,3 Pan Am. World Airways 41 5640 2,7
Northwest Airlines 42 5868 2,9 Northwest Airlines 43 4593 2,1
Delta Air Lines 35 8798 0,5 Continental Airlines 44 1793 0,3
American Airlines 37 9281 0,5
Continental Micronesia 35 2027 0,5 Continental Airlines 29 10731 0,3
Totals 38 6810 7,9 Totals 42 4957 5,1
Table 3.8: The fuel consumption per ASK of the American air carriers in 1982 and 1999 in pacific traffic42
Source: [DOT 2001].
As it was mentioned in Section 3.4, the overall fuel consumption figures coupled with the overall figures for the amount of ASKs and RPKs transported in 1997 suggest that the US air carriers consume around 39g per ASK and 56g per RPK (see Figures 3.1 and 3.3). However, the data provided by the US Department of transport on the operating statistics of all the US air carriers makes it possible to deduct the fuel consumed by the all-cargo carriers [DOT 2001]. The Grand totals that are shown in Column 2 in Table 3.9 are estimates for the specific fuel consumption per ASK including the all-cargo carriers, while the totals in Column 3 in Table 3.9 are estimates
41 See footnote above.
42 See footnote above.
that excludes the fuel consumed by the all-cargo carriers. The fourth column in Table 3.9 shows how much the Grand totals are reduced when subtracting the fuel that is consumed by the all-cargo carriers. Column 5 in Figure 3.9 shows the passenger airlines’ share of the total fuel consumption. Our calculations suggest that the specific fuel consumption per ASK that is shown in Figure 3.3 is reduced by 3 percent in 1982 and this share increases over the years to 12 percent in 1999 because the all-cargo carriers consume an increasing share of the total consumption. Thus, the specific fuel consumption per ASK of all US passenger carriers is around 35g in 1999. If taking an average load factor of around 71% [DOT 2000, p. 258] into account, the overall specific fuel consumption per RPK is about 49g (as compared to the 56g when including the all-cargo carriers).
The data used for these calculations do not allow for calculating the specific fuel consumption of all the all-cargo carriers because the data used for these calculations do not include information on the revenue freight tonne kilometres (RFTK) transported [DOT 2001].
Grand totals incl all-cargo
Totals excl all-cargo
Difference between Grand
totals and Totals
% of fuel consumed by these carriers
included in the totals
[g/ASK] [g/ASK] [%] [%]
1982 43,2 41,8 -3 96,9
1985 41,1 39,3 -4 97,5
1990 41,2 38,3 -7 92,7
1995 39,6 35,5 -10 89,5
1999 39,8 35,0 -12 87,6
Table 3.9: Correction of the specific fuel consumption of American carriers taking into consideration the amount of freight that is carried by all-cargo operators43.
It should be noted that these data are calculated (by the author of this report) on the basis of data provided by the US Department of Transport on the fuel consumed and the ASKs produced by all American air carriers in a number of years.
Source: [DOT 2001]
43 Note that the author of this report has revised the 1985 data because United Airlines’ fuel consumption was not reported in the spreadsheet data received from the United States Department of Transport. United Airlines carried some 12% of total ASKs in 1985. The fuel