Low level, night, formation, tac flying and airdrop - the sport of Kings!
Although the memory of mid-winter nights spent at Londonderry DZ sends chills down my spine!
The USAF guys would often track direct from Richmond to Nowra, over Penrith, Camden an past Wilton at 240KIAS/500' AGL in the middle of the day and without a single call!
The RAAF guys, operating a tac cse in the Sydney basin, would have ATC providing information and separation for them, so no real dramas.