title: Facet and Fill in R
body: <p>I am trying to plot a total delay (in mins) vs aircraft name graph faceted by 12 months. The data set (p) that I am using has some variables like total delay, weather delay (in mins),carrier delay (in mins), aircraft  name. (total delay = sum of 2 variables weather delay+carrier delay)
  I want fill as 2 variables (weather delay, carrier delay etc)
  I am able to plot a total delay vs aircraft but do not know how to fill in each bar with values of the 2 variables weather_delay and carrier delay.</p>
  
  <pre><code>ggplot(subset(p, airport %in% c( "IAD")) + 
         aes(x= aircraft_name, y = total_delay, color = airport) + 
         geom_histogram(stat ="identity",binwidth=1) + 
         facet_grid(~month,scales='free')
  </code></pre>
  
  <p>The problem I am facing is the dataset contains variables like weather delay, carrier delay, security delay which sum up to the total delay. I want to show every bar of total delay as a component of the 3 delays. The fill part should consist of the 3 variables delays.</p>