INSIGHT – Comparing seat miles per gallon |

The US Department of Transportation compiles economic data from airlines regarding operating costs, with fuel being one of those key elements. We examined our airline operating cost model and developed a comparative fuel metric, which is seat miles per gallon. The data for our models are updated about 6 months after the close of a calendar quarter, so our current data is through the 3rd quarter of 2021. Our models, available free to subscribers, update automatically based on the latest available data. Our dataset includes fuel usage information, in US gallons, by aircraft type and airline, dating back to 2010. Our dataset also includes the average seating for each aircraft type, which we have also broken down by airline, and by type of carrier (network, low-cost carrier, and ultra-low-cost carrier.) As a result, we can provide multiple interesting comparisons between aircraft of various sizes. The 737NG and A320ceo families The mainstay of airline fleets today remains the 737NG and A320ceo, which are now being replaced by the 737 MAX and A320neo. Let’s compare the seat miles per gallon of these types along with the number of seats offered. The Airbus A320 family began service in 1989, and the Boeing 737NGs eight years later, in 1997. As a result, we would expect the Boeing model to be more efficient for two reasons. The first is incorporating new knowledge during those eight years, and the second is that Boeing could optimize its offering around a slightly larger size of the baseline 737-800 against the A320ceo. Let’s look at the results for the A320 and 737-800. When we examine the results for all carriers, including network, low cost, and ultra-low-cost carriers, the 737-800 holds an advantage over the A320ceo in terms of fuel per seat mile, averaging 7.6% better results, 4.5% of which comes from a higher number of seats. The table below summarizes the data by year for the two types: If we restrict the analysis to only network carriers, the results widen, with the 737-800 holding an 11.6% fuel advantage, 6.7% of which comes from higher seating capacity, as shown in the table below. Moving downward in gauge, the 737-700 holds an advantage over the A319ceo, with a 12.4% advantage in fuel burn, of which 6.1% can be attributed to seating capacity. The following table summarizes those results for all carriers. Interestingly, when one moves to network carriers, the seating capacity reverses to favor the A319ceo, and the fuel burn advantage for the 737-700 narrows to 4.5%. This is likely because the seating layouts are different between low-cost and network carriers. Also, Allegiant (a ULCC), now uses the A319ceo. At the top of the narrow-body market, the A321 and 737-900ER square off. The 737-900ER model was introduced later than the A321, so our table below shows a comparison from 2014 onward rather than from 2010. While the A321 has an average 2.7% advantage in seating capacity, the fuel advantage goes to the 737-900ER, which has a 10.4% advantage, as shown in the table below: The Bottom Line: The 737NG Series has an advantage in fuel efficiency against the A320ceo family across the board. Stay tuned, as we examine the neo family against the MAX family in a future Insight.

US Flight Planner - US DoT On-Time Data	Airbus vs Boeing - Official OEM Data
US Airline Schedule Performance - US DoT Data	Daily OEM Production & Deliveries -

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