An airline reports a record quarter: more passengers than ever, planes more than 80% full, revenue up strongly. Two quarters later, with the same planes just as full, it reports a loss. Jet fuel had risen about ten per cent and the rupee had weakened a little. Nothing went wrong with the airline’s operations. It is simply a business whose profit is a thin slice between two large numbers, and a small move in either one is enough to change its sign.
A shared taxi on a fixed route leaves at the scheduled time whether it has four passengers or two. The driver’s fuel, the car’s instalments and his own day’s wage are the same either way. He makes money only if enough seats are filled at a fare that covers them — and if diesel goes up, the fare often cannot, because the next taxi in line will take his passengers.
An airline is that taxi at enormous scale. Once a flight is scheduled, almost all its cost is committed. Profit depends on how many seats are sold, at what fare, against a cost per seat that fuel and the dollar can move at any time.
The vocabulary: seats, kilometres and fares
| Metric | What it measures | Why it matters |
|---|---|---|
| ASK (available seat-kilometres) | Seats flown × kilometres flown — the airline’s capacity | The denominator for everything else; capacity growth is the airline’s own choice |
| RPK (revenue passenger-kilometres) | Paying passengers × kilometres flown | What was actually sold |
| Load factor | RPK ÷ ASK | How full the planes were |
| Yield | Passenger revenue ÷ RPK | The average fare per kilometre flown by a passenger |
| RASK | Total revenue ÷ ASK | Load factor and yield combined, plus ancillary revenue |
| CASK | Operating cost ÷ ASK, often shown with and without fuel | The cost base; CASK excluding fuel shows efficiency the airline controls |
- Ancillary share
- baggage, seat selection, meals and other non-ticket revenue, as a share of ticket revenue
- Breakeven load factor
- CASK ÷ (Yield × (1 + ancillary share)) — the share of seats that must be sold to cover costs
Example: At a yield of ₹5.50 per passenger-kilometre and 10% ancillary revenue, each seat-kilometre sold earns ₹6.05. With a CASK of ₹4.70, the airline breaks even when 77.7% of seats are filled.
Change the load factor, fares and fuel, and watch the spread between RASK and CASK — and the breakeven load factor.
Why so much of the cost is in dollars
- Fuel. Aviation turbine fuel is priced off international benchmarks and is usually the largest single cost. Indian taxes on jet fuel have also been high by global standards.
- Aircraft leases. Most Indian airlines lease rather than own their aircraft, with rentals set in dollars.
- Maintenance and engines. Spare parts, engine overhauls and maintenance contracts are largely paid in dollars. Engine problems that ground part of a fleet raise costs while cutting capacity.
- Revenue, by contrast, is mostly in rupees for a domestic airline. A weaker rupee therefore raises costs without raising revenue — a direct hit to the spread.
Structure matters more than any single airline
Because the spread is so thin, the fare level set by competition decides the industry’s profit. A market with a few disciplined carriers can keep fares above cost; a market with a new entrant buying share, or a struggling airline selling seats below cost to raise cash, can make everyone unprofitable. The history of Indian aviation includes Kingfisher Airlines stopping flights in 2012, Jet Airways in 2019 and Go First in 2023. When one carrier exits, the survivors often gain pricing power — which is why an airline’s results can improve sharply without any change inside it.
An airline flies 85% full, but its breakeven load factor is 88%. It is most likely:
Airline har seat-kilometre bechti hai. RASK (har seat-km ki kamai) − CASK (har seat-km ka kharcha) = munafa — aur yeh gap sirf kuch paise ka hota hai. ₹4.84 kamai, ₹4.70 kharcha = 14 paise × 10,000 crore seat-km = ₹1,400 crore. Fuel 10% mehenga hua toh CASK ₹4.89 — seedha ₹500 crore ka ghaata, plane utne hi bhare the. Fuel, lease, maintenance sab dollar mein, kamai rupaye mein. Load factor ko breakeven load factor se compare karo. Kingfisher, Jet, Go First — sabka sabak: bure saal ke liye cash chahiye.
- Airline profit is RASK minus CASK — two large numbers with a gap of a few paise.
- RASK combines load factor, yield and ancillary revenue; compare the load factor with the breakeven load factor.
- Fuel, leases and maintenance are largely dollar-linked while domestic revenue is in rupees.
- Under Ind AS 116 EBITDA excludes aircraft rentals; check lease liabilities and strip out sale-and-leaseback gains.
- Industry structure and fare discipline decide profits more than any one airline’s efficiency.
Mark it done to track your progress through the curriculum.
Common questions
Short, direct answers to what people ask about this topic.
- RASK and CASK meaning for airlines
- RASK is revenue per available seat-kilometre and CASK is cost per available seat-kilometre — an airline’s revenue and operating cost divided by its capacity, the number of seats flown multiplied by the kilometres they travel. The gap between them is the airline’s profit per unit of capacity. Because both are several rupees and the gap is usually a few paise, small changes in fares, fuel or the rupee decide whether an airline makes money.
- what is a good load factor for an airline
- There is no single good number, because what matters is the load factor compared with the airline’s breakeven load factor — the share of seats it must fill to cover its costs at current fares. A carrier filling 85% of seats can still lose money if its breakeven is 88%, while one filling 78% can be profitable at a lower cost base. Indian domestic carriers typically fly with high load factors, which is why fares and costs, not filling seats, usually decide profit.
- why do fuel prices affect airline stocks so much
- Because aviation turbine fuel is usually an airline’s largest single cost, and its price follows global crude oil and the dollar. The profit margin per seat-kilometre is so thin that a 10% rise in fuel cost can wipe out a year’s operating profit unless fares rise to match — and airlines cannot always pass it on quickly when competitors keep fares low.
- why have so many Indian airlines gone bankrupt
- Because the business combines thin margins, high fixed costs, costs linked to the dollar and fierce fare competition, so a period of high fuel prices, a weak rupee or a price war can exhaust an airline’s cash quickly. Kingfisher Airlines stopped flying in 2012, Jet Airways in 2019 and Go First in 2023. When analysing an airline, cash in hand and the ability to survive a bad year matter as much as the profit in a good one.