While fighters are vital for any modern space force in human space, their are many ways for such craft to be launched from a ship.
The simplest is the use of EXTERNAL HOUSING, holding fighters on individual hardpoints or in racks with multiple fighters. While this allows for east deployment of fighters by vessels not originally designed to hold them or too small to realistically carry the more complex systems, external houskng of fighters greatly limits a ship's ability to repair and rearm its fighters, especially while under thrust. It also makes it hard for pilots to board their foghters, meaning this method is best done with drone fighters.
For larger vessels, the use of FLIGHT BAYS is more effective for the deployment of their fighters. These bays allow for the launch and retrieval of fighters from internal bays designed to house them, making the operation, rearmament, and repair of a vessel's fighter complement far easier. Many flight bays carry the fighter themselves, but others, often those on larger ships, simply launch and retrieve them, with the fighters held in a desicated hanger amoung other fighters. Some bays can carry multiple fighters within them, though these hanger bays can rarely launch all of then at once.
While flight bays and external housing are mass and space efficant, they provide a chalange for fighter retrieval, making such operations rather lengthy and increasing the time for a fighter to be rearmed and sent back out. Full FLIGHT DECKS solve this problem by being able to launch or retrieve multiple fighters at once, often entire squadrons at a time. This does come with significant drawbacks, however, flight decks are large and becoming a significant fixture of any vessel that is equipped with one, either taking over an entire external section of the ship or being built directing into the hull. This leaves flight decks as exclusive to dedicated carrier vessels, with other ship classes making due with the less effective launch measures.