Becoming a commercial airline pilot meaning someone who flies passengers or cargo for an airline is a thrilling and serious goal. When we talk about what is a commercial airline pilot we refer to someone who holds appropriate licences qualifications and flight hours to command or co pilot large aircraft in paid operations. The number of flying hours required to reach this level varies significantly depending on the country the licence type and whether one is aiming to be a First Officer or a Captain.
In many jurisdictions (for example in India under the Directorate General of Civil Aviation (DGCA) regime), aspiring pilots must log a minimum of around 200 flying hours to obtain a Commercial Pilot Licence (CPL). This includes solo flying, pilot-in-command (PIC) time cross country flying, instrument time and night flying. Meanwhile in other regions (such as the United States under the Federal Aviation Administration (FAA)) the requirement might start around 250 hours for certain commercial pilot rights. These hours allow you to fly for hire (crop dusting charter aerial work) but not yet necessarily to act as pilot in command of large airline multi-crew jets.
If your ambition is to become an airline pilot flying for a commercial airline (i.e., what is a commercial airline pilot" in the sense of scheduled passenger/cargo operations) the required hours are far higher. For example in the U.S. to act as pilot-in-command for major airlines or in multi pilot operations the FAA typically mandates 1,500 total flight hours. That means after earning your CPL and building experience you must accumulate many hundreds of additional hours (in different conditions on complex aircraft likely including jet time) before you're eligible for the airline transport pilot certificate or equivalent. In Europe and other regions the hours may vary but often still run into the high hundreds or low thousands especially for multi engine multi crew aircraft.
The reason for such large hour requirements is experience. Operating as a commercial airline pilot involves far more than simply flying the aircraft. You must be ready to handle complex aircraft systems work as part of a multi crew cockpit deal with abnormal situations weather traffic varying airports and schedule pressure. The large number of hours helps ensure that pilots have enough exposure to diverse flight conditions time of day (including night) different weather cross country flights instrument conditions and multi crew coordination. In short: the more hours you log in meaningful conditions, the safer and more competent you become.
If you're dreaming of becoming a commercial airline pilot you should plan for a multi stage journey:
First you need to get your basic licences (Private Pilot License Instrument Rating Commercial Pilot Licence).
Then build hours through instruction charter aerial work etc. while gaining varied experience.
Then aim for the airline entry level job (First Officer) which in many cases will require hundreds to over a thousand hours of flight time.
Then, with more hours and seniority you may progress to Captain on larger aircraft.