New Data-Support Tool Lowers Costs and Increases Efficiency for Today’s Airlines

Nils Alt, Jürgen Ringbeck, Stefan Spinler - May 27, 2025

Aviation is an industry defined by ferocious competition and several operational challenges: The revenue that airlines earn per passenger is low; the fixed costs they incur, however, are immense. And on top of that, airlines are considerably vulnerable to external macroeconomic factors. How successful the business will be is therefore contingent on the airline reducing costs wherever feasible. But now, aviation analyst platform Skailark, founded by alumnus Christian Soyk, has collaborated with WHU – Otto Beisheim School of Management to give airlines a new way to drastically reduce their high operational costs—even at the final stages of the process.

Under the hood—and even under the paint

One thing driving up costs is routine maintenance of the aircraft. From the visual checks and the “walk around,” which occur before each flight, to the more detailed inspections and general repairs that need to be made over time—airlines have to implement numerous measures to comply with the standards set out by the civil aviation authorities.

Aircraft maintenance includes, but is not limited to, “letter checks,” i.e., A, B, C, and D checks, the last of which being particularly comprehensive, costly, and time consuming. It occurs once every six years and even sees the plane stripped of its painted finish and deconstructed to its most basic components, with trained engineers checking each for signs of wear and tear. Exactly how much the D check costs depends on the average age of the fleet, on which types of aircraft are part of said fleet, and on the country where maintenance occurs. Generally speaking, this major reconditioning costs several million euros—per vehicle. Together, C and D checks account for 12% of the money airlines spend, making it advantageous for airlines to explore ways of cutting costs. 

Large datasets allow for comparison

WHU’s experts, together with Skailark, have developed a competitive intelligence tool (CI-tool) that allows for a comparison of airline data that is significantly more transparent—particularly for the D check. It makes use of Skailark’s  extensive collection of non-proprietary industry data that covers everything from the costings and earnings to the maintenance and operations of over 300 different airlines. In comparison to conventional benchmarking methods, Skailark’s Digital Twin produces analyses that are highly up-to-date and easy to understand by combining a variety of data concerning fleets, flight positions, and other dimensions and processing them with the help of analytical and statistical models. Airlines can acquire these datasets and compare their own output and methodologies to those of their competitors, which, in turn, can help identify where there could be significant savings potential.

Where should airlines get their fleets inspected?

The CI-tool allows us to look at the costs associated with separate D-checks performed for a pair of Airbus 320-200s: one aircraft owned by a full-service American airline and the other by a budget-friendly Mexican airline. The most appreciable difference between these checks was the country where the refurbishing efforts took place. The American airline serviced their aircraft domestically, whereas the Mexican airline sent their aircraft to an offshore operation in El Salvador. The CI-tool revealed that the full-service airline could have saved around 33% of its costs (per flight hour) had it also sent its aircraft to El Salvador for maintenance in accordance with the same safety standards. That difference reflects 6.4% of the airline’s maintenance costs per flight hour for this aircraft, thereby revealing significant potential savings for airlines that have their fleets serviced in the United States or the European Union.

Central America and South-East Asia are popular regions for certain airlines seeking a D check. Given that the maintenance facilities situated in those areas for American and European airlines require the same certifications from the same civil aviation authorities, there is no difference in the quality of the D checks performed.

The CI-tool also helped compare the associated maintenance costs of two different types of aircraft, the Boeing 747-400 and the Boeing 787-9, both belonging to airlines based in Europe. The analysis showed that the maintenance of the 787-9 was over 23% cheaper (per flight hour) than that of the 747-400, taking into account the latter’s higher seating capacity. Of course, any cost advantage will lessen as the airplanes age.

The CI-tool is designed to deliver reliable cost estimations to today’s airlines and thereby have an effect on an airline’s fleet-related decisions and where aircraft are serviced. Additionally, it allows the airline to better understand when it makes the most sense to refurbish its fleet in order to keep maintenance costs low, something rather advantageous for airlines active in a highly competitive market.

Literature reference

- Alt, N. (2025): Dynamic Aircraft Maintenance Cost Benchmarking: Developing a Competitive Intelligence Tool embedded in Skailark’s Digital Twin of Aviation, Master Thesis.