6:38, I don't really understand what he meant when he said that we stopped the spinning of air. Did he mean that we stopped singing with support? 

Hi, Tan! To me, that could refer to 2 things: (1) not supplying air to the vocal folds, usually by "locking up" the surrounding muscles or using too much compression - and I'd help fix that by using a warmup syllable that contains a consonant with some air flow (like a "sh", "s", or "th" sound); or (2) spinning air referring to vibrato usage.