I have heard this expression hundreds of times.

Sometimes at staff development, they show cartoon figures building a plane in mid-air.

Note that the engineers are wearing parachutes.

Note that the passengers–students and teachers–have no parachutes.

Bear in mind that the idea of building a plane as it is in mid-air is insane.

The next time you hear this expression, do one of these things:

Get up and walk out.

Hiss loudly (no one ever knows who is hissing)

Boo loudly (riskier than hissing)

Do not quietly sit by while your leader spouts idiotic platitudes.