There are no insurance companies that can afford that or that would back it, including Berkshire Hathaway (and they're among the only ones that could even attempt it).
If you tried it, you'd just take down the entire insurance industry again as they suddenly might have to eat $100 billion in losses across the segment in one year, paying out epic cash that nobody outside of Apple, Microsoft and Google have to pay out.
This is exactly the scenario where you should socialize losses across the giant government with the Fed's printing press and balance sheet, and simultaneously also ensure the government and its taxpayers get a fair deal (the airlines have to pay it back, and or taxpayers get the equity which can be sold off and receive dividends over time; all the US airlines were worth maybe $90 billion prior to the crash, producing like $18b in operating profit per year).
Most likely, the price of flights would be an order of magnitude greater if airlines weren't (through various direct and indirect means) publicly subsidised.
That's what insurance is for.
If an airline can't afford to buy adequate insurance, then it isn't actually a profitable businesses.
If market pressures make it impossible for airlines to run operations in a financially responsible way, then that may illustrate the fact that markets don't always create the best outcomes.