While the video above shows Bowie just waving do bear in mind that he had form in this department having said in 1974:
'Britain is ready for a fascist leader… I think Britain could benefit from a fascist leader. After all, fascism is really nationalism… I believe very strongly in fascism, people have always responded with greater efficiency under a regimental leadership…'And in the September 1976 Playboy issue carried this quote:
BOWIE: Rock stars are fascists. Adolf Hitler was one of the first rock stars.It is interesting that most people will just shrug Bowie's 'salute' off and blame it (if indeed it happened) on his excessive use of cocaine at the time.
PLAYBOY: How so?
BOWIE: Think about it. Look at some of his films and see how he moved. I think he was quite as good as Jagger. It’s astounding. And boy, when he hit that stage, he worked an audience. Good God! He was no politician. He was a media artist. He used politics and theatrics and created this thing that governed and controlled the show for 12 years. The world will never see his like again. He staged a country […] People aren’t very bright, you know? They say they want freedom, but when they get the chance, they pass up Nietzsche and choose Hitler because he would march into a room to speak and music and lights would come on at strategic moments. It was rather like a rock ‘n roll concert. The kids would get very excited – girls got hot and sweaty and guys wished it was them up there. That, for me, is the rock ‘n roll experience.
Clapton's drunken onstage racist monologue from the same year is (rightly in my opinion) never really blamed on the alcohol though