<http://blog.covingtonaircraft.com/wp-content/uploads/2013/08/History-of-Aviation-Part-Seven.jpg>
<http://schema.org/primaryImageOfPage>
<http://blog.covingtonaircraft.com/wp-content/uploads/2013/08/History-of-Aviation-Part-Seven.jpg#primaryimage>
<http://blog.covingtonaircraft.com/2012/03/02/history-of-aviation-part-seven-todays-aviation/history-of-aviation-part-seven/>