Yes, infants can have their own seat on a flight, but it requires that you buy a separate ticket for the child instead of traveling with the infant on your lap. Many choose this for better comfort, easier sleep, and greater control during the journey, especially on longer flights.
Ticket and equipment that are usually required
During takeoff and landing, the infant must sit on an adult’s lap with a special belt that is fastened around the infant and the adult. This belt is available on board the aircraft and is provided by the airline. At all other times during the flight, the child may then sit in their own airplane seat. If you bring your own car seat, you should check with the airline whether it is allowed on board, since requirements may vary regarding labeling, dimensions, and how the seat is secured, and sometimes you need to book a seat where the car seat is compatible with the aircraft seat model.
What you should check before booking
Read the airline’s rules for infants, an own seat, and approved child seats before you buy the ticket, and also check what applies to carry on baggage and checking in baby equipment. If you are traveling with connections, it is especially important that the same conditions apply on all segments, so you avoid surprises at the gate.