I haven't looked through the Met Life paperwork, but usually an Aviation exclusion comes in the form of a rider attached to the policy, basically saying that life insurance doesn't cover loss if the insured was a pilot/crew in an aircraft. This rider is actually very common in most life insurance policies.

In other words, I think if an aviation exclusion rider can't be found anywhere, the implication is that death by aviation is included in the policy (i.e. it's not excluded.) I'm also curious if anyone has found anything.