[victorbjorklund]

In the air. If the force applied is not the normal force expected from normal use it might be intended to snap off.

[stouset]

This is like suggesting that a boat's hull is designed to snap off in the event it encounters unexpected forces outside the water.

[account42]

I can see a boat's hull be designed to crumble as safely as possible under a headson impact. But the situation is not the same. Boats usually stay in water at all times. An accident might put them under water. The situation is different with airplanes: all airplanes are guaranteed to eventually impact the ground, just ideally in a controlled manner.

[victorbjorklund]

Parts of the boats are def made to snap off when unexpected force is applied.