Found this note on StackOverflow.
"From what I can establish, Google tests the availability of a connection prior to deciding whether to use offline or online recognition. If a connection is available initially but is lost prior to the response, Google will supply a connection error, it won’t fall-back to offline."
That seems to describe your testing.
And I just tested, VR works in airplane mode.
"From what I can establish, Google tests the availability of a connection prior to deciding whether to use offline or online recognition. If a connection is available initially but is lost prior to the response, Google will supply a connection error, it won’t fall-back to offline."
That seems to describe your testing.
And I just tested, VR works in airplane mode.