An airline is a company that operates airplanes to transport passengers and cargo from one place to another. When your family flies to visit relatives or takes a vacation, you're using an airline's services. Major airlines like Delta, United, and Southwest own or lease fleets of aircraft, employ pilots and flight attendants, and manage complex schedules connecting cities around the world.

Airlines sell tickets for specific flights, check in passengers, handle luggage, and provide food and drinks during longer journeys. They maintain their planes carefully, following strict safety regulations. Some airlines focus on short domestic trips, while others specialize in long international routes crossing oceans and continents.

Before airlines existed, long-distance travel meant spending days or weeks on trains or ships. Today, airlines make it possible to fly across the country in hours or reach another continent overnight. Running an airline requires enormous coordination: managing thousands of employees, maintaining expensive aircraft, scheduling flights efficiently, and keeping passengers safe and comfortable at 30,000 feet above Earth.