可是你都没有用到forecast包

很抱歉，我误解了你的问题，我将使用`forecast`包生成四种趋势图并生成关于季节性趋势的图表。首先，我们需要加载`AirPassengers`数据集和所需的包：

library(forecast)

data(AirPassengers)

接下来，我们可以使用`autoplot`函数绘制四种趋势图：

1. 线图

autoplot(AirPassengers) +
  labs(title = "AirPassengers Time Series Plot",
       x = "Year",
       y = "Passengers")

2. 点图

autoplot(AirPassengers, geom = "point", color = "red") +
  labs(title = "AirPassengers Time Series Plot",
       x = "Year",
       y = "Passengers")

3. 点线图

autoplot(AirPassengers, series = "Passengers") +
  labs(title = "AirPassengers Time Series Plot",
       x = "Year",
       y = "Passengers")

4. 区域图

autoplot(AirPassengers, series = "Passengers", fill = "blue") +
  labs(title = "AirPassengers Time Series Plot",
       x = "Year",
       y = "Passengers")

接下来，我们可以使用`stl`函数来绘制季节性趋势图：

decomposed_ts <- stl(AirPassengers, s.window = "periodic")
autoplot(decomposed_ts$time.series[, "seasonal"]) +
  labs(title = "Seasonal Trend of AirPassengers Time Series")

这将绘制出AirPassengers时间序列的季节性趋势图。

希望这可以满足你的需求。