Final answer:
When two aircraft are approaching each other head-on, the aircraft on the left should give way to the aircraft on the right.
Step-by-step explanation:
When two aircraft are approaching each other head-on, the aircraft should pass to the right of each other. This is known as the 'right-of-way' rule and is similar to the rule of driving on the right side of the road. The aircraft on the left should give way to the aircraft on the right, ensuring a safe distance between them.