Cool things with wheels since 2006
When escorting bombers, the fighters commonly flew high above them to protect from the German fighters. As they were a overheard protection it became known as umbrella coverage. Their job was to keep the enemy away from the bombers. They could not do that if they were flying at the same altitude as the bombers so they stayed high above and then dropped down unto the enemy formation.
I hope you've read that I'm losing my memory, and here's an example, dang it. Because, I've posted mission symbols, and posts about WW2 fighters many times and mentioned the umbrella symbol for bomber top coverage missions. http://justacarguy.blogspot.com/2016/09/the-mattie-ii.html Thanks for the reminder!