Glorious exposed early-war failures to follow carrier doctrine

What operational failures most likely led to the loss of HMS Glorious?

The likeliest explanation is a wartime failure of awareness and carrier operating practice rather than a decisive secret mission, with Glorious left dangerously lightly escorted.

The likeliest explanation is that forces can temporarily behave as if peacetime habits still apply, particularly early in a conflict. Glorious sailed with only two destroyers despite a peacetime tendency to accompany carriers with much stronger screens. That decision departed from the carrier doctrine associated with Reginald Henderson. Senior officers expected better reconnaissance and protection for a carrier and its trained air group.