Guide
Empty legs and emissions: what can honestly be said
Empty legs are often sold as the greener way to fly private. Some of that is true by definition, some of it is marketing, and the line between the two is worth drawing carefully. This guide keeps to what follows from how empty legs work, and says plainly where we have no figures.
What an empty leg is
A charter aircraft flies where its customers pay it to go. After a drop off, or before a pick up, it has to move to its next job or back to base, and that flight is scheduled by the operator whether or not anyone buys a seat on it. That repositioning flight, published for sale at a reduced price, is the empty leg. It exists because of the previous or the next charter, not because of you.
What follows from that
Buying an empty leg does not add a flight. The aircraft was going to fly that sector anyway. This is the one solid claim, and it holds exactly as long as the flight really was going to happen: the same date, the same airports, the same aircraft, as published. If an operator changes the routing to suit you, the sector is no longer the one that was already scheduled, and the claim weakens with every change.
Passengers add weight, and weight adds fuel burn. An aircraft flying with people and bags on board burns more fuel than the same aircraft flying empty on the same sector. The difference depends on the aircraft and the load; it is not zero. So "zero emissions" is wrong even for a perfect empty leg; "no additional flight" is right.
The alternative matters. If the empty leg replaces a charter you would otherwise have booked, one flight has replaced two aircraft movements: yours, and the operator's empty repositioning. If it replaces a scheduled airline seat you would otherwise have taken, the airline flight still departs and the comparison is different. Which case you are in is something only you know.
What cannot honestly be said
"This flight is carbon neutral" or "zero emissions". A jet burning fuel is neither. Offsetting is a separate transaction with its own evidence; an empty leg on its own is not an offset.
"You saved X tonnes of CO2". That figure would need the fuel burn of the sector, the marginal burn from your weight, and an assumption about what you would have done instead. We do not compute it and we do not publish one. If an operator gives you a number, ask what it assumes.
"Empty legs make private flying sustainable". Empty legs are a by-product of charter demand. Filling them uses a flight better; it does not change how many flights the charter market generates.
A caution from our own record
An empty leg is only an "already happening" flight until the operator's plans change. Since 30 July 2026 we have recorded published legs, and of them left the board before their departure date. Some were sold; some were withdrawn because the aircraft was no longer going that way. We cannot tell which from the outside, and neither can a buyer. It is one more reason to treat the "no additional flight" claim as true for the flight you actually take, on the day, and not as a general property of the category.
What we do on this site
We list empty legs as the operators publish them, with the operator's own price where there is one, and we do not attach an emissions figure to any leg. If we ever do, it will come with the method and the assumptions on the same page. Until then, the honest summary is short: an empty leg is a flight that was scheduled anyway, you add a little weight to it, and what you would have done instead is the part that decides whether it was the better choice.
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