Axl Rose is on to the next one ... his Guns N' Roses days are done -- for now -- and he's already got AC/DC on the brain. We just got Axl cruising through LAX on one of those scooter thingys. Broken foot and all, he's jetting off to Europe to join his OTHER band. Of course, Axl is standing in for Brian Johnson during AC/DC's upcoming tour dates ... and he revealed which song he's most looking forward to belting out. He'll be with AC/DC now through mid-June and then back to GN