public function addPassenger(Passenger $passenger)
    {
        if ($this->passenger === null) {
            $this->passenger = [];
        }

        $this->passenger[] = $passenger;

        return $this;
    }
public function addPassenger(Passenger $passenger)
    {
        if ($this->passenger === null) {
            $this->passenger = [];
        }

        $this->passenger[] = $passenger;

        return $this;
    }
@param Passenger $passenger

@return Flight