This tribute to the Gray Eagles (WWII pilots) was in conjunction with an air show in Ohio called 'The Final Roundup.' It was the last large gathering of the remaining P-51 Mustang fighters used during WWII. There were about 120 of the fighters there...all of them in flying condition, of course.
The flyover seen at the end of the video is composed entirely of P-51s spelling out the number 51.
It was an event that will never be seen again.
The greatest generation. The last generation not to suffer from attention deficit. They did not quit till the job was done.
http://www.grayeagles.org/video.htm