Sky-writing

Apparently there is a guy who does most of the sky-writing along Australia's Eastern Seaboard. I know this because my boss met him over the holiday break. He was at the Camden airport and was in town to do skywriting for the start of the Sydney-Hobart Race and also to do a big question mark above the harbour on New Year's Eve. I have always been enthralled by skywriters and how they draw their symbols in the sky - how they know how to form the letters. So I asked the boss if he'd found out how it was done - and he said yes ... he had - but what he'd found out was how they made the smoke - not how they used it. But he thinks he will see him out at the airport again and, if he does, he will certainly ask more questions!