them against both damage to their ai-? rcraft and their liability to passengers.

Is this a limited or unlimited liability? Reason?

I don't believe insurance carriers would cover someone on an "unlimited liability" basis. The risk is too great to cover any person or business that way. Insurance carriers will limit their coverages by endorsements to the policy. Normally, insurance companies will cover everything but what is excluded in each individual policy. It would take too long for an insurance company to list what they will cover on an insurance policy. Instead, they only list what they will not cover.

There is always a certain limit to all policies. If the sky is the limit, then the insurance company would go broke.