The film has been around for a while now - you can find a transcript/description of the footage and some details
here
Richthofen was replaced as commander of JG1 by Wilhelm Reinhard; he was killed in a flying accident in July and Goering replaced him.
Reinhard and Goering both attended the flying trials, and after Goering had flown a prototype Dornier-Zeppelin D.I, Reinhard had a go; the top wing separated from the aircraft in a dive and he was killed. It transpired that the aircraft was meant to be grounded because of structural weakness, but as some observers have noted, had Reinhard had the first flight and then hopped out to let Goering have a try, the history of the Third Reich might have been very different indeed...