"Old-fashioned manned planes" work. It's not riskier to bet on the sure thing that has an upgrade path (in the event that drone AI does make the jump, it's not like a modern fly-by-wire plane won't be able to be retrofitted) to the potential new thing.
I take your point about uncertainty of AI, particularly in light of growing concerns that self driving cars are a lot further off than predicted.
But in regard to betting on drones being risky, surely betting on old fashioned manned planes is riskier?