Corporate Travel Buyers Add Airline Sustainability To Metrics

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Corporate travel procurement increasingly will be decided not just on traditional metrics—including price, airline network, schedule, flexibility and loyalty rewards—but also on the stated sustainability strategies of airlines and the demonstrated outcomes of decarbonization commitments.

To ensure that a company’s sustainability objectives are supported by the actions of travel suppliers, including airlines, it is critical that corporate procurement divisions have access to meaningful and detailed performance data from airlines to demonstrate not only the existence of sustainability strategies, but also demonstrated actions and evidence of outcomes.

A report by CAPA and carbon reduction strategist Envest Global recommends and describes a two-stage process that firstly selects preferred air carriers based on their whole-of-airline sustainability performance. Secondly, it makes individual flight choices from these preferred providers based on credible flight-specific information and options to offset emissions and/or purchase sustainable aviation fuel (SAF).

The 52 airlines analyzed in this report collectively produced approximately 70% of the industry’s total carbon emissions in 2019, or approximately 916 million tonnes.  

CAPA-Envest recommends a whole-of-airline approach to assess sustainability performance. This incorporates all aspects of airline operations, including cargo operations, and therefore balances the uncertainty and variability introduced by a range of flight-specific factors, including load factor, aircraft age and type, cargo load and journey delays in the air and on the ground. 


It also avoids reliance on flight-specific emissions estimates provided by carbon calculators, which generate a wide range of estimates depending on assumptions embedded in calculation methodologies. 

And it provides a more robust basis for estimating carbon emissions and comparing these to emissions in prior years, which adds rigor and confidence to sustainability reporting and tracking progress toward stated sustainability and carbon reduction goals.

This whole-of-airline approach should comprise an assessment of an airline’s total global business and consider a range of important sustainability indicators and performance metrics (see box).

A whole-of-airline assessment approach provides a foundation for developing an airline sustainability rating system that can be used to readily assess the sustainability credentials of airlines and for selecting preferred providers for incorporation in a company’s travel program.  

The report also provides a summary of the factors to consider in making individual flight buying decisions once a whole-of-airline assessment has identified a group of preferred airlines and an appropriate level of sustainability performance. These include:

Carbon emission estimate: There are significant differences in the carbon emission estimates of different carbon calculators evaluating the same city-pair flight.  Given the obvious and significant variability in carbon emission estimates, it is recommended that companies adopt a single carbon calculator for all city-pair emission estimates to ensure a degree of consistency. 

Class of travel: The carbon emission allocation by passenger is typically allocated as a proportion of net floor area occupied by the passenger and the associated cabin facilities, such as number of toilets and galleys. The allocations for different classes of travel will vary by airline and aircraft depending on the seat configuration.  

Aircraft type: It is beyond the scope of the report to quantify typical emissions by aircraft type, but the fuel efficiency and therefore the carbon emission intensity of aircraft has improved with each new aircraft and engine model released.

Non-stop vs indirect flight options: Direct, non-stop flights typically emit less carbon than indirect flights, including stopovers, assuming similar aircraft models. 

The full report can be accessed at