I had a pretty cool encounter with one about 6-7 years ago, I was on a driving holiday and we were cruising throught the Ikara-Flinders Ranges National Park doing about 90-100km and one of these guys just casually comes up to my window, so close I could have grabbed it. It must have picked some drag effect off the van like a wake in the air or something and it was just gliding next to us with the occasional flap for a good 5 minutes until there was an incoming car and it ducked out