The UK’s Civil Aviation Authority has released guidelines on the type of environmental information that should be provided to airline passengers when they are searching and booking flights.
The CAA’s new framework, published on 5 February, aims to improve the availability of standardised flight emissions data at the point of sale, and follows a 2024 consultation and 2023 “call for evidence” involving the aviation and wider travel sectors.
It sets out guidance for airlines and “other booking organisations”, but is only applicable to flights that are advertised and sold in the UK and which depart from or arrive at UK airports.
The CAA advises that flight emissions information should be calculated based on "actual route specific data, including actual fuel burn and passenger loading" – rather than methodologies based on distance-based averages, like the commonly used DEFRA standard.
Carbon emissions methodologies recommended by the CAA include the Department for Energy Security and Net Zero (DESNZ) estimates for UK aviation emissions, IATA’s Practice Per-Passenger CO2 Calculation Methodology, the EASA Flight Emissions Label and Google’s TIM.
“We acknowledge that these methodologies do use different approaches to estimating fuel burn… These do result in different estimates, but we consider that these are within an acceptable tolerance for long-haul and medium-haul flights,” the CAA stated. “We therefore do not intend, at this stage, to recommend one above the other.”
Stakeholders involved in the CAA's 2024 consultation warned of "complex technological challenges" when integrating emissions information into global distribution systems and booking platforms. In the corporate travel ecosystem, however, several technology providers exist to address this challenge.
Kit Aspen, co-founder of sustainability specialist Thrust Carbon, and said “most booking platforms will already be compliant [with the framework] from day-one thanks to their existing carbon data providers, and for those that do not have this data the integration cost will be minimal.”
Aspen also supported CAA’s recommended list of methodologies – where emissions are calculated upon 'actuals' rather than generic averages – but cautioned that gaps remain.
“The CAA has insisted on better methodologies for the purpose of 'consistency' – which we think is great – but then made no decisions on the specific areas that actually cause inconsistencies, such as contrail impact of SAF usage. Instead these contentious areas are 'encouraged' and left to be decided upon later,” he said.
Aspen added that the “very narrow” scope of the framework could also result in platforms “having a multitude of methodologies to support the flights and/or points of sale that don't fall under these regulations. So, we find it extremely disappointing that the CAA is not working closer with international bodies.”
Adherence to the framework is currently on a voluntary basis, with the aviation regulator looking to track adoption rates until April 2027, at which point it may “consider additional actions and whether a mandatory approach is necessary”.