How travel platforms should explain sustainable aviation fuel offers

When a customer adds a sustainable aviation fuel (SAF) contribution to a booking, the fuel they pay for may never go near their flight. Under book and claim, the system SAF registries are built on, what they buy is a certificate.

The RSB Book & Claim Manual, the rulebook for RSB's SAF registry, spells it out: the customer's money buys a certificate for SAF delivered somewhere in the fuel system. The airline named on the certificate is "the exclusive owner of the Scope 1 emission reduction" in every case, and the customer gets a Scope 3 claim at most.

That gap between what "add SAF" sounds like and what it delivers is where checkout copy goes wrong.

In November 2025, after talks with the European Commission and EU consumer authorities, 21 airlines committed to stop claiming that a specific flight's CO2 could be "neutralised, offset, or directly reduced" by customer payments "for the use of alternative aviation fuels." If you sell or pass through those payments, your checkout copy is describing the same product.

The checklist of fields to get from the airline or SAF provider, and to show the customer, is at the end. For SAF itself (pathways, supply, prices), see our fact pack on SAF, carbon credits and renewables. None of this is legal advice.

What the customer buys: a registry certificate

ICAO's training material on SAF accounting lists three ways to track a fuel's green attributes through the supply chain: physical segregation, mass balance, and book and claim. Most of what follows assumes the third, so check which one your provider uses.

Book and claim, in RSB's words, "allows organisations to obtain and claim the sustainability attributes of a product without having to take physical custody of that product." The manual is plain about what that means for the buyer: "the customer may not physically utilise the specific sustainable fuel or product to fly or ship their goods." What they have is a record in a registry.

That's a legitimate product. RSB describes it as a way of linking "limited supply locations with global demand," so a customer can pay for SAF at an airport that has none. But it's a different product from the one "fly on SAF" suggests, and your first job in the copy is to say which one you're selling.

IATA estimates that SAF production in 2025 equaled only 0.6% of all jet fuel used, and expects 0.8% in 2026. A customer who reads "your flight uses SAF" will picture far more than that.

Who can claim the reduction: Scope 1 and Scope 3

RSB's manual allows "one organisation to claim a Scope 1 reduction and up to two organisations to claim Scope 3 reductions" for each certificate. The airline named on the retirement statement always holds the Scope 1 claim. Your customer can be one of the Scope 3 claimants, and the route there decides what you can tell them.

Leisure travelers: an allocation from the airline

Under section 5.2.1, an airline that retired certificates for its own use "may allocate the Scope 3 emission reduction to its passengers," including by "allocating it to individual passengers who purchase the reduction with their ticket." The airline does the allocating. Ask it how it calculates each passenger's share and whether the passenger's name, or only the airline's, appears on any record.

Business customers: their name on the retirement statement

Section 5.2.2 is stricter. When certificates are retired for a corporate customer, the Scope 3 reduction "belongs exclusively to the Corporate End-User mentioned on the retirement statement." A company that wants to report what it paid for needs that statement in its own name, and section 5.6 caps the claim at its "total air travel and air freight footprint in that reporting year."

If your platform sells to companies (a TMC, a corporate booking tool, a benefit provider), ask the provider whether the offer produces a retirement statement in each customer's name. RSB is explicit that "any exclusive Scope 3 claims must be declared in a retirement statement issued by the Registry."

Where double claiming happens

RSB defines double claiming as "two or more companies" claiming "the same GHG emission reduction within the same scope." The quieter version is in the emission factor. RSB's section 6 says a reduction shared with a corporate customer "shall not also be counted within a jet fuel emission factor that can be used by the airlines' other customers."

Airlines do flag this. Air New Zealand's 2026 climate statement says its intensity figures "include SAF emissions reductions allocated to customers and should not be used by customers for their own emissions reporting, as this may result in double counting." If your platform shows per-flight CO2 estimates, ask each airline whether its figures already include SAF that other customers paid for.

Fuel already counted toward a mandate or CORSIA

CORSIA, ICAO's offsetting scheme for international flights, deals only with airlines' Scope 1 emissions. ICAO's material says "Scope 3 emission reduction claimed by corporations against voluntary schemes is not addressed within CORSIA."

Registries handle the overlap differently. At launch, the SAFc Registry's rules issued only the airline's Scope 1 certificate for SAF used toward "a blending mandate or other ineligible scheme (CORSIA, some incentives)," with no customer certificate.

RSB requires any national incentive or government policy to be "accurately declared" when the certificate is registered. Either way, ask whether the fuel behind your customers' certificates also counted toward a mandate.

Which registries issue SAF certificates

Three registries record SAF certificates that airlines and companies can claim. CORSIA is the regulatory scheme they work alongside.

Whichever registry the provider uses, get the certificate or retirement statement number for each purchase. RSB counts registering the same batch of fuel in two registries as "double use," and the number is how anyone checks it.

What published consumer-protection texts say about SAF wording

Regulators and consumer networks have already written about how SAF contributions get described. Here is what they say, in their own words. Whether any of it applies to your platform, and how, is a question for your own counsel.

European Commission and EU consumer authorities, November 2025. Among the commitments discussed with 21 airlines: "Clarifying that the CO₂ emissions of a specific flight cannot be neutralised, offset, or directly reduced by contributions to climate protection projects or alternative aviation fuels," and "Using the term 'sustainable aviation fuels' only with appropriate clarifications to substantiate it."

ICPEN, May 2025. The open letter to the aviation sector, signed by 17 consumer authorities, says that when the consumer pays for offsets or SAF, "these measures should not be marketed as measures made by the airline, other than as a facilitator." For SAF claims, it suggests "contextualizing the amount of fuel (e.g., through reference to total fuel usage) and the amount of emissions reduction achieved per unit of fuel."

US FTC Green Guides. Section 260.4(c): "Marketers should not imply that any specific benefit is significant if it is, in fact, negligible." The section on carbon offsets asks sellers to use methods that "ensure that they do not sell the same reduction more than one time."

UK CMA Green Claims Code. Two of its six principles bear most directly on a SAF add-on: "claims must not omit or hide important relevant information" and "claims must consider the full life cycle of the product or service."

UK Advertising Standards Authority, 2023. In its ruling on a Lufthansa search ad for a SAF-and-offset fare, the ASA said limited ad space didn't mean "material information of such relevance could be omitted." A one-line checkout toggle has the same space problem.

For how a buyer tests these claims from the other side, see our guide to assessing airline climate claims in procurement. Generic phrases like "carbon neutral" are covered in the climate-impact claim checklist.

The checklist: what to get from the provider and what to show the customer

Get these fields in writing before the offer goes live, then refresh them whenever the provider, registry or fuel source changes. Most of them appear on an RSB retirement statement, so a provider using that registry should have them on hand.

From the airline or SAF provider

At checkout and on the receipt

• What the payment buys: a certificate for a stated quantity of SAF, on a named registry.
• What it doesn't change: the fuel in this flight's tanks, and the flight's emissions. The airlines' November 2025 commitment wording is a useful model.
• The reduction: in kilograms of CO2e, against the fossil baseline, with the method a click away.
• Scale: the amount of fuel in context, for example as a share of the flight's estimated fuel. ICPEN suggests a "reference to total fuel usage."
• Who claims what: the airline keeps the Scope 1 reduction. Say what the customer can claim, if anything.
• For business customers: a retirement statement in the company's name, and a note that claims are capped at its air travel footprint for the year.
• The record: the registry, the statement number and the date it'll be issued.

Put together, a receipt line that covers those points reads something like this:

"Your contribution bought certificates for [X] kg of SAF on the [registry], statement [number], retired on [date]. This SAF was delivered into the fuel system at [location] and may not have been used on your flight. Its lifecycle emissions are about [Y] kg of CO2e lower than the regulator's baseline for fossil jet fuel. The airline counts that reduction in its own direct emissions, and the Scope 3 claim is [yours / allocated by the airline]."

Fill every bracket from the provider's fields above, and get your counsel to review the final text.

Where Dyme fits

Dyme books flights on more than 600 airlines and doesn't sell a SAF contribution, so none of the above describes a product of ours. What our bookings do is help fund new solar: 5.5 MW built and generating across the projects we've helped fund, with 20 MW more in the pipeline. Those figures aren't independently audited.

We describe that as funding solar, and we don't tell members it reduces a flight's emissions. Benefits platforms and membership organizations offer Dyme to their employees and members, who book hotels and flights at member rates. If you'd like your members' bookings to fund solar too, we're happy to talk it through.