There ought to be a clear distinction between a
protest and
direct action.
Protests are about sending a certain message to a certain target audience.
Direct action is about physical and immediately either doing a concrete thing (e.g. Food Not Bombs) or preventing a concrete thing (e.g. chaining yourself to a tree so it can't be cut down).
(Incidentally strikes can fit into either depending on their context and form)
Was the Plane Stupid thing a Direct Action or protest?
It seems to be not quite manageing to succeed at either imo.
It was DA of a sort. It stopped planes from operating. But only a very very limited scale.
It was protest of a sort. It got publicity and spread a message. But as we've seen here, this has had mixed results.
So, I think it was a mistake.