Airline load factor is the share of available seats that are filled with paying passengers. A flight with 150 of 200 seats sold has a load factor of 75 percent. It is one of the first numbers analysts check, because an airline’s costs barely change whether a seat is occupied or empty, so each extra passenger adds revenue at little extra cost.
A high load factor does not guarantee profit, though. What matters is how it compares with the load factor the airline needs to cover its costs, and at what fare the seats were sold.
How load factor is calculated
Airlines measure traffic and capacity in kilometers or miles, not just in passengers and seats, so that long and short flights are weighed properly. IATA defines revenue passenger kilometers (RPK) as the number of revenue passengers multiplied by the distance traveled, and available seat kilometers (ASK) as the number of available seats multiplied by the distance flown. Passenger load factor is RPK divided by ASK.
A short example shows the arithmetic. If 150 paying passengers fly a 1,000 km sector on a 200-seat aircraft, RPK is 150,000 and ASK is 200,000. Load factor is 150,000 divided by 200,000, or 75 percent. The figures are invented for illustration.
What the industry numbers look like
IATA reported that the overall passenger load factor for full-year 2024 reached 83.5 percent, which it described as a record for full-year traffic. Its release attributed the high level partly to supply chain constraints that limited how quickly airlines could add capacity. Load factors differ by region, airline type and season, and figures for later periods are published on IATA’s website.
Industry averages hide wide variation. A flight at a quiet hour or on a seasonal route may run far below average, while flights at peak times can be close to full.
Why a full plane matters
An aircraft flying a scheduled route has most of its costs locked in before the doors close: the aircraft itself, the crew, the fuel for the sector and airport charges. A passenger adds relatively little on top, such as catering, handling and some fuel burn for the extra weight. That is why filling seats moves profit more than most other levers. A seat that departs empty cannot be sold later, so the revenue is lost permanently.
Break-even load factor
The break-even load factor is the load factor at which an airline’s revenue exactly covers its operating costs. The relationship follows from the definitions. Revenue equals the load factor times ASK times yield, where yield is the average revenue earned per RPK. Costs equal ASK times cost per ASK (CASK). Setting revenue equal to costs and cancelling ASK gives:
Break-even load factor = CASK ÷ yield
Two things follow. If costs rise and fares stay the same, the break-even point moves up, so the airline needs fuller planes to avoid a loss. If fares rise and costs stay the same, the break-even point falls.
A worked example
Using invented numbers, suppose an airline’s cost per ASK is 6.0 cents and its yield is 8.0 cents per RPK. Its break-even load factor is 6.0 ÷ 8.0, or 75 percent. At an actual load factor of 82 percent the airline earns an operating margin on the flight. At 70 percent it loses money. If the airline cut fares to lift the load factor to 85 percent but yield fell to 6.5 cents, the break-even point would become 6.0 ÷ 6.5, about 92 percent, and the flight would lose money despite being full.
Load factor and yield pull in different directions
The example shows the central tension. Lower fares fill seats but reduce yield. Higher fares protect yield but leave seats empty. Airlines manage the balance through revenue management: they release seats in fare buckets, raise prices as a flight fills and try to hold seats for late-booking passengers who pay more. A very high load factor can mean the airline priced too low and sold seats it could have sold for more. A low one can mean prices were too high or capacity was too large.
Ancillary revenue adds another factor. Fees for bags, seats and extras earn money per passenger, which changes the break-even calculation. How these fees work is covered in the article on how airlines earn money beyond the ticket.
Limits of the measure
- It ignores fares. Two airlines with identical load factors can earn very different revenue.
- It ignores costs. A low-cost airline can break even at a lower load factor than a high-cost one.
- It averages across routes. A network can have an acceptable overall load factor while some routes lose money.
- It depends on capacity choices. Cutting flights raises load factor without necessarily raising profit.
Frequently asked questions
What is a good load factor?
There is no single answer. It depends on the airline’s costs and fares. A good load factor is one comfortably above the airline’s own break-even point on that route.
Is a higher load factor always better?
No. A full flight sold at very low fares can earn less than a flight with some empty seats sold at higher fares.
How is load factor different from seat occupancy?
In everyday use the terms mean nearly the same. Load factor is the formal industry measure, calculated from RPK and ASK so that distance is accounted for.
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