[Rainer]

The answer to this question is more complicated as you would think. The German efficiency had strict rules how someone could be nominated to receive the Knight's Cross and until his death on 30 April 1945 it was Hitler himself who ultimately decided if it was awarded or not. On the day he died some 33 proposals for this award were ready to be signed. His successor Dönitz sent a list of staff positions authorized to award the Knight's Cross on 3 May 1945, but legally only those awarded until and including 8 May 1945 can be valid.

According to the German historian Veit Scherzer about 200 alleged awards of the Knight's Cross are currently disputed as no official documentation or evidence of the award can be found. The cases of Herbert Bareuther and Heinz Unrau are two of them, furthermore the proposal of the award for Josef Baldes was never finalized.

The last confirmed award of the Knight's Cross to a member of the Luftwaffe went to Hptm Hans Beyer, Staffelkapitän 3.(F)/33, on 1 May 1945.

@Adriano
The video you mentioned was the last public appearance of Hitler and taken on 20 March 1945, one month before his last birthday. The last member of the Luftwaffe to receive an award personally from Hitler could have been Rudel on 1 January 1945.