Currently in like Feb or March. I've got 4 bases (getting to that later), plasma researched and Marauders up and running.
The only terror thing that ever appeared was a Bomber with two escorts. A pop-up came up something about terrorizing a city and requesting interceptors to the site. So I did. I sent some interceptors, destroyed the bomber and its escorts .. and that was it. The Soviet Union was extremely happy with it, though, as I'm pretty sure the funding increased by like 100k.
I haven't seen any proper terror missions, nor base assaults. I've done three alien base missions, because South America was undefended (without radar coverage) for a looooong time. I built a base in North America, not knowing that a base in Middle America would be sufficient to cover both N and S America. That resulted in two alien bases and reduced down to 44k funding before I managed to get a base with a radar and two marauders up there. The third base appeared somewhere in Siberia, which was sneakily established outside of the radar range of Europe's base in Malta and the Asian base in Indonesia.
Not expecting any terror missions, bases or base assaults from now on, though. I've got absolute control of the air.