In 2026, the three largest operating expenses for global airlines remain Fuel, Labor, and Aircraft Maintenance/Leasing. Fuel is the most volatile and significant cost, often accounting for 25% to 35% of total expenditures; as oil prices fluctuate, so do airline profit margins. Labor (salaries for pilots, flight attendants, and ground crew) is the second major cost, representing roughly 20% to 25% of the budget. The third pillar is Aircraft Ownership and Maintenance, which includes the massive monthly lease payments for planes like the A350 or 787, as well as the "heavy checks" required by aviation authorities. In 2026, many airlines are also seeing a rise in "Environmental Levies" as a fourth significant cost, but the "Big Three" remain the primary drivers of the ticket prices you see on travel sites today.