How to assess airline climate claims for procurement

In July 2023, a Lufthansa search ad in the UK told readers they could "Fly more sustainably." When the UK's advertising regulator asked what that meant, Lufthansa said it referred to its Green Fares option, which covers 20% of a flight's CO2 with sustainable aviation fuel and offsets the other 80%. The Advertising Standards Authority ruled the ad misleading because it didn't say any of that.

The same gap can turn up in an airline sales deck or RFP response, where a short claim stands in for a specific product and the detail only appears when someone asks. So when you're assessing an airline's climate claims for a procurement round, ask the same thing first every time: which part of the product does this describe, and what's the evidence?

You don't have to invent the follow-up questions. Between 2023 and 2025, courts and consumer regulators, most of them in Europe, ruled on airline climate ads and published their reasoning. Their findings make a good checklist for an airline evaluation.

The claims regulators flagged

In April 2024, the European Commission and the EU's network of national consumer authorities wrote to 20 airlines about six kinds of claim they considered potentially misleading. In November 2025, 21 airlines committed to change their practices, among them Air France, KLM, Lufthansa, Ryanair, easyJet and SWISS.

Those actions were about advertising to consumers. But the same kinds of claim can turn up in a corporate pitch. Here are the six, plus percentage claims, with what to ask for:

The consumer side of these cases, for someone booking a single trip, is in our guide to spotting greenwashing when you book travel. The sections below take each claim from the buyer's side.

Generic claims: ask which part of the product they cover

The ASA ruled against three airline ads on the same day, December 6, 2023. Lufthansa's was the 20/80 fare above. Etihad's ad offered "Total Peace Of Mind" alongside the words "Environmental Advocacy." Air France's said it was "committed to protecting the environment: travel better and sustainably."

For the last two, the ASA said absolute claims like these need "a high level of substantiation," and that there were "no initiatives or commercially viable technologies in operation within the aviation industry" that could provide it. Air France-KLM didn't give the regulator a substantive response.

In March 2024, the Amsterdam District Court went through 19 KLM ads and statements from its "Fly Responsibly" campaign, its CO2ZERO product and a fare sale, and found 15 of them misleading. The court didn't ban the word "sustainable." In our translation from the Dutch, it said that when a company uses vague terms like that, "it is up to the user (KLM) to make clear to the consumer what is meant in this specific case."

ICPEN's May 2025 letter to the aviation sector, signed by 17 of its member authorities, makes the same point about evidence. A claim that an airline recycles its uniforms needs evidence for that one claim. A vague claim like "fly sustainably" implies the whole service is sustainable, so the substantiation required "is likely to be extremely high, if not prohibitive."

For your evaluation, that gives you a simple rule. When a response calls a carrier sustainable, green or responsible, ask which measure the word refers to. Then score the measure and ignore the word.

Offset claims: ask for the projects, the timing and who pays

All 21 airlines that made commitments in 2025 agreed to stop claiming that a specific flight's CO2 "could be neutralised, offset, or directly reduced" by customers paying into climate projects or alternative fuels.

The Amsterdam court reached similar conclusions about KLM in 2024, in our translation. KLM's CO2ZERO name suggested "zero CO2 emissions," which the court called "an absolute and far-reaching term." The court also found "no direct link" between what a customer paid and the emissions of their own flight. It called the effect of the reforestation project "uncertain," partly because it wasn't clear the trees would stay standing.

If a carrier offers to offset your company's flights, ICPEN's letter lists the evidence an airline should be able to provide. The credits should be "additional, permanent, issued against a conservative baseline, quantified, monitored, reported and verified," with "a clear and transparent chain of custody," and "not double-counted, double-claimed, or double-issued." Turn that list into your evidence request, and add:

• the projects by name, and the registry record showing the credits were retired and for whom
• when the reductions happen. The FTC Green Guides say marketers should disclose when an offset's reductions won't happen for two years or longer
• whether the reductions were required by law anyway, which the Guides also treat as deceptive to sell as an offset
• who pays. ICPEN says that when the customer pays for offsets or SAF, the airline shouldn't present them as its own measures, "other than as a facilitator"

Keep the offset off the emissions figure. The industry's own calculation standard, IATA RP 1726, doesn't let an airline's offsets reduce a passenger's CO2 figure. Our guide to sustainability criteria in a preferred airline program covers that rule and how to write it into a contract.

SAF claims: ask for the share, the reduction and who claims it

Sustainable aviation fuel is real, and there isn't much of it yet. IATA estimates that SAF made up only 0.6% of all jet fuel used in 2025. That's why a claim like "flying on SAF" needs a number next to it.

ICPEN's example is "all our flights fly on sustainable aviation fuels," which it says consumers could take to mean every flight runs on 100% SAF. It asks airlines to give the amount of SAF as a share of total fuel use and "the amount of emissions reduction achieved per unit of fuel."

ICPEN also says any claim that SAF cuts emissions by a set amount should rest on a life-cycle analysis covering "all relevant impact categories," beyond CO2 alone.

In our translation, the KLM court found that the fare-sale ads' claim that SAF cuts CO2 by "at least 75%" compared with fossil fuel wasn't sufficiently substantiated. It also noted that SAF's share of KLM's fuel, and so of its CO2 reduction, was still "very limited."

Ask each carrier for three things: the SAF share of total fuel for the period in the claim, the lifecycle reduction it uses and the method behind it, and who claims the reduction.

ICPEN asks airlines to avoid "double counting, double claiming, and double issuance," so if your company pays for a reduction, ask how the airline keeps it out of its own figures. We'll cover corporate SAF purchases, and how they're accounted for, in a separate guide.

Percentages and comparisons: ask for the baseline and the method

A claim like 15% lower emissions, or the most fuel-efficient fleet, can be true and still tell you little. Ask what the percentage is measured against, per what unit, over which years, and by which method.

The FTC Guides say marketers "should not imply that any specific benefit is significant if it is, in fact, negligible." ICPEN puts it more concretely: an airline cutting single-use plastics in its cabin is "likely to be misleading" if presented as making the airline more sustainable, because it "does not significantly change the airline's total environmental impact."

The EU authorities also flagged flight comparisons made "without providing sufficient and accurate information on the elements the comparison is based on."

If two carriers send you per-trip figures, check that they used the same method before you compare them. Our guide to assessing airline emissions data covers the method choices behind those figures, and why the same flight can report nearly five times the emissions.

Net-zero targets: ask for the plan behind them

A target is a claim about the future, and the EU and ICPEN both want a plan behind it. For consumer advertising, the EU's Directive 2024/825 says future-performance claims should rest on "a detailed and realistic implementation plan" with "measurable and time-bound targets," checked regularly by an independent expert.

ICPEN asks for "concrete targets and timeframes." Judging the targets themselves gets its own guide.

A checklist for your airline RFP

You can add this as a short section to the airline RFP you already send:

1. List every environmental claim. Ask each carrier to list every environmental claim it makes in its response and sales materials, and attach the evidence for each one.
2. Name the product. For each claim, say which fare, route, program or aircraft it covers. A claim about one fare option goes in the evaluation as a claim about that fare option.
3. Date the evidence. ICPEN says documentation should cover the whole claim "during the relevant marketing period." Ask when the figures were measured.
4. Separate what you'd pay for. Offsets and SAF offered to your company get their own line, price and reporting, apart from the emissions figure.
5. Ask about changes. If the carrier is one of the 21 that made commitments to EU authorities in 2025, ask whether any claim in its response changed as a result.
6. Use the method questions. For any CO2 figure, ask the questions in our travel supplier climate questionnaire.

Then score the evidence. A carrier with one well-documented measure should beat one with a page of adjectives.

For the hotel side of the same program, our guide to building hotel sustainability criteria into procurement asks the same documentation question of hotel RFP answers.

Where Dyme fits

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