Aerolva Airlines runs at an 80% load factor with an EBIT margin of 3%. About 80% of its costs are fixed for the season. If the load factor rises to 85% at the same fares, what happens to the EBIT margin?

A 6.25% rise in revenue lifts EBIT from Rs 240 crore to about Rs 643 crore and the margin from 3.0% to about 7.6%. With 80% of costs fixed, each extra passenger's fare, less a small variable cost, falls straight to profit. The same arithmetic runs the other way: Aerolva breaks even at a 77.0% load factor, only three points below today, which is why airline earnings swing so hard on small changes in demand.

A bus that runs whether it carries twenty people or forty costs almost the same to operate either way, so the twenty-first passenger's fare is nearly all profit. An airline's costs for a season are set when it fixes its schedule, so once the planes are flying, extra passengers add revenue far faster than they add cost. Aerolva's costs are Rs 7,760 crore: Rs 6,208 crore fixed and Rs 1,552 crore variable, which is 19.4% of revenue. Each extra rupee of fare brings about 81 paise of profit.

Revenue scales with passengers at the same fares: 85 / 80 is 1.0625, so revenue rises to Rs 8,500 crore. Variable costs scale the same way, to Rs 1,649.0 crore. Fixed costs stay at Rs 6,208 crore. EBIT rises from Rs 240 crore to Rs 643.0 crore, up about 168%, and the margin from 3.0% to 7.6%. This is operating leverageHow much profit moves for a given move in revenue. The larger the share of fixed costs, the bigger the swing. in its purest form: a 6% move in revenue becomes a 168% move in operating profit.

Less than the arithmetic suggests. The extra five points of load factor are usually sold at lower fares, because the last seats on a flight are the ones an airline discounts to fill, so the same-fares assumption overstates the gain. If the new passengers pay 20% less than the average fare, the extra revenue is Rs 400 crore rather than Rs 500 crore, and EBIT reaches about Rs 543 crore rather than Rs 643 crore. Fuel also rises a little with the weight carried. The direction of the answer holds; its size is better stated as a range.

The investor's reading is the one that matters. A breakeven load factor of 77.0% against a current 80% means Aerolva has about three points of cushion before it loses money, so its earnings are highly sensitive to demand in either direction. That is why analysts watch monthly load factors and fares so closely, and why an airline's shares often move more on a traffic update than on its annual results.