Airlines have spent years learning how to monetise the journey around the seat: bags, meals, lounge access, insurance, hotels, car hire. Mobile data is now joining that shelf.

The interesting question is not whether an airline can sell an eSIM. It can. The useful question is whether the income deserves space in an already crowded booking journey.

For a carrier handling millions of international passengers, modest conversion can produce six- or seven-figure annual revenue. But passenger eligibility is not a sale, and checkout value is not airline income.

Airline economics leave little room for lazy arithmetic. IATA has repeatedly highlighted the importance of ancillary revenue. A digital product with no catering truck, baggage handler or physical inventory attached deserves attention. It does not deserve fantasy.

A model airlines can actually use

The safest approach is scenario modelling, not pretending there is one industry-standard attach rate.

Assume three airline sizes: 1 million, 5 million and 20 million annual international passengers.

For the working case, assume 5% buy an eSIM, the average order is €18, and the airline retains 25%. Deduct €0.35 per order for payment leakage, refunds, support and operations, plus €150,000 yearly for integration, merchandising, analytics and programme management.

These are assumptions, not market averages. Suppliers rarely publish airline revenue shares, while terms vary with volume, branding, customer ownership, support responsibilities and distribution model.

The formula:

Passengers × 5% attach rate × €18 order value × 25% airline share, minus €0.35 per sale and €150,000 fixed cost.

Three traffic scenarios

“Contribution” means the airline’s share after the stated variable and fixed programme costs. It is not audited operating profit. Corporate tax, wider overhead and passenger-acquisition costs sit outside the model.

At one million passengers, €57,500 does not justify an elaborate build. A referral arrangement or co-branded page is a more sensible test.

At five million, nearly €900,000 in annual contribution can justify proper merchandising, destination-led offers and app integration.

At 20 million passengers, roughly €4 million starts to look like a meaningful ancillary line.

And that is using a 5% attach rate, not a heroic one.

Conversion decides the economics

Now push the model.

At 3% conversion, contribution is approximately minus €25,500 for a one-million-passenger carrier, €472,500 at five million passengers and €2.34 million at 20 million.

At 10%, those figures rise to roughly €265,000, €1.93 million and €8.15 million.

That range tells us more than any single headline number.

The smaller airline has to be disciplined. Conversion can decide whether the programme earns money. Large airlines have more room because volume absorbs fixed costs quickly.

Placement matters.

An eSIM buried beside carbon offsets in a post-booking email will not behave like one shown in the airline app 24 hours before departure. Destination, trip duration and roaming arrangements matter. Someone flying inside an inclusive roaming zone may reasonably ignore the offer. So may a traveller with a corporate phone or a premium plan that already covers the destination.

The strongest proposition is contextual: “5GB for Japan, ready when you land” is better than “Buy an eSIM.”

Referral or embedded retail?

There are several routes today.

Affiliate distribution is cheap and fast. It can validate demand without much technical work, but the airline usually gives up margin, branding, behavioural data and control over support.

A co-branded storefront sits in the middle.

Full API integration gives the airline the cleanest customer journey and potentially stronger economics, but it also brings product, privacy, payments and customer-care responsibilities.

Yesim’s Partner API is one example of that embedded route, allowing airlines and other travel brands to place connectivity directly inside their own digital journey rather than sending passengers elsewhere to shop. The wider market is clearly moving in the same direction, with more providers offering white-label, API and embedded connectivity models designed specifically for travel companies. The real differentiation is no longer simply who can supply an eSIM, but who gives the airline enough control over branding, pricing, customer experience and post-sale support to make the product feel like part of the airline journey rather than an external add-on.

The models differ. One airline may want incremental commission. Another may want pricing control, loyalty integration, traveller data and a branded connectivity product it can reuse across future trips.

Those are very different businesses.

Where providers still need to improve

The weakest part of the airline eSIM pitch is often the evidence.

Airlines should demand anonymised conversion benchmarks by channel and destination, refund and activation rates, support-contact ratios, device-compatibility failures and repeat-purchase data.

“New revenue stream” is not a business case. Neither is quoting total eSIM sales without showing the airline’s retained economics.

There is also operational risk. At 20 million passengers and a 10% attach rate, two million eSIMs are sold. A seemingly harmless 1% support-contact rate then produces 20,000 cases.

That is why the cheapest wholesale rate is not necessarily the best deal. Installation recovery, clear fair-use rules, network performance, support and data visibility can be worth more than another percentage point of margin.

Conclusion

For a one-million-passenger airline, eSIM should probably begin as a controlled test. At five million international passengers, it can become a credible ancillary business. At 20 million, treating connectivity as a minor sidebar starts to look shortsighted.

The strongest business case is not “airlines can make millions from eSIM.” Some can. Some will not.

The more interesting point is that airlines now have a realistic way to monetise connectivity while keeping the passenger inside their digital environment after landing.

That is where Yesim and its competitors are really competing: not simply for eSIM transactions, but for a place inside the airline customer journey.

The winning carrier will not ask only, “How much commission do we make per sale?” It will ask what a connected passenger is worth across rebooking, app engagement, ground transport, loyalty, future travel and the next purchase.

The eSIM revenue matters.

Owning the connected arrival may matter more.