To bring the insurance conversation back full circle, the basic foundation of insurance is that it deals with "pure risk", which is the chance of loss or no loss, but no chance of gain. As others have mentioned, insurance companies aren't dumb, they typically won't over insure an aircraft. Does it happen? Sure, now and then, but typically no. In the airline world polices have deductibles just like your homeowners, or your Cessna 172 policy and they usually are between $1,000,000 and $500,000 dollars depending on model, body type, etc. So the airline will eat that first chunk of money before insurance kicks in. If there are upgrades to the aircraft the value is adjusted. If there is damage that is being repaired, the value is lowered until the repairs are complete. So in the end, the insureds typically don't make a profit in the event of a total loss, insurance has plenty of checks and balances that naturally prevent that. Has it happened? Yep, I've seen it(and believe me, the fallout isn't pretty for the underwriters) but it is rare. And if there is suspected fraud involved, insurance companies will do a deep investigation; they have lawyers on staff and they'll hire outside counsel if need be. Chances are the insurance companies has been doing this much longer than the insured has been around, so they're not to be messed with.