diff --git a/internal/domain/pln.go b/internal/domain/pln.go
new file mode 100644
index 0000000..f96aa21
--- /dev/null
+++ b/internal/domain/pln.go
@@ -0,0 +1,79 @@
+package domain
+
+import "fmt"
+
+type FlightSchedule struct {
+	// Date of the flight schedule.
+	// Example: "30OCT"
+	Date string `json:"date"`
+
+	// Category of the flight schedule. It could represent different categories based on the airline or flight type.
+	// Example: "H/G"
+	Category string `json:"category,omitempty"`
+
+	// Flight number of the flight schedule. This is a unique identifier for the flight.
+	// Example: "CA1014"
+	FlightNumber string `json:"flight_number"`
+
+	// Aircraft registration number. This is a unique identifier for the aircraft used for the flight.
+	// Example: "B2458"
+	AircraftReg string `json:"aircraft_reg"`
+
+	// Passenger configuration or seating arrangement for the flight. This field may include details about class configurations.
+	// Example: "1/1"
+	PassengerConfig string `json:"passenger_config,omitempty"`
+
+	// Instrument Landing System (ILS) category or configuration used for the flight. This field may include ILS category details.
+	// Example: "ILS(0)"
+	ILS string `json:"ils,omitempty"`
+
+	// ICAO code for the departure airport.
+	// Example: "ZBTJ"
+	DepartureAirport string `json:"departure_airport"`
+
+	// Scheduled departure time of the flight. This field may be formatted as HHMM or include date information.
+	// Example: "1845"
+	DepartureTime string `json:"departure_time,omitempty"`
+
+	// Additional schedule information. This field may include special instructions or additional scheduling details.
+	// Example: "SI:TSN1845"
+	ScheduleInfo string `json:"schedule_info,omitempty"`
+
+	// Estimated or scheduled arrival time of the flight. This field may be formatted as HHMM or include date information.
+	// Example: "2100"
+	ArrivalTime string `json:"arrival_time,omitempty"`
+
+	// ICAO code for the arrival airport.
+	// Example: "ZSPD"
+	ArrivalAirport string `json:"arrival_airport"`
+
+	// Additional comments or remarks about the flight schedule. This field may include any relevant notes or observations.
+	// Example: "Special cargo handling required"
+	Comments string `json:"comments,omitempty"`
+
+	// Reference information or external identifiers related to the flight schedule. This field may include references to external systems or documents.
+	Reference string `json:"reference,omitempty"`
+}
+
+func (f *FlightSchedule) Validate() error {
+	if f.Date == "" {
+		return fmt.Errorf("date is required")
+	}
+	if f.FlightNumber == "" {
+		return fmt.Errorf("flight number is required")
+	}
+	if f.AircraftReg == "" {
+		return fmt.Errorf("aircraft registration is required")
+	}
+	if f.DepartureAirport == "" {
+		return fmt.Errorf("departure airport is required")
+	}
+	if f.ArrivalAirport == "" {
+		return fmt.Errorf("arrival airport is required")
+	}
+
+	if f.DepartureTime == "" && f.ArrivalTime == "" {
+		return fmt.Errorf("either departure time or arrival time is required")
+	}
+	return nil
+}