Under what conditions can you fly in IMC without an IFR flight plan?

Mildred's people

In uncontrolled (Class G) airspace. You must be on an IFR flight plan when in CONTROLLED airspace (per FAR 91.173), but you could legally take off from an uncontrolled field, and fly around in IMC as long as it was Class G airspace. But you still must hold an instrument rating. And tooling around in IMC at low altitude in Class G airspace is a really bad idea as well.

Anonymous

Under an IFR flight itinerary in uncontrolled airspace.

Anonymous

Ok