From my point of view and personal experience they are very similar/overlapping. There are also some important differences?
Hypnosis is like quieting the conscious mind, the chattering monkey mind, and submitting suggestions directly to the subconscious mind.
In normal waking life the chattering conscious mind, the ego, is doing its thing running scripts/programs, and through hypnosis we can stop the unconscious ramblings of the ego and reprogram the core processing system of our brain with new and better programs/habits.
In flow states, the ego/chattering monkey mind also goes quiet. The body is running on autopilot. One can ?zone out? or ?get in the zone? or become aware of the zone in all its glorious zone-ness.
A flow state could easily be described as a moving meditation.
Hypnosis is generally used for a specific purpose. For example, someone wants to quit smoking. They go to a hypnotist that basically removes the addiction program and replaces it with a cigarettes are gross program.
So someone might go into a hypnotic trance to allow the hypnotist the opportunity to ?reprogram? that habit.
Whereas in a flow state that is not the intention.
A flow state is similar in that you go into a trance, but it is a higher awareness level trance.
You are conscious of doing the thing, yet, you don?t seem to be the one doing it 🙂
It?s as if you are a passenger in the ride that is your life.
You may experience time distortions; you were having so much fun that you ?lost track of time.?
Where were you when you lost your connection to ?objective time??