IF both the President and VP are incapacitated or killed, the Speaker of the House would be sworn in as President, her aircraft designated AF1 and she would be flown back to DC to take to make a speech.
But they would have to get both Trump and Pence at the same time. If Pence takes over, Pelosi would remain Speaker of the House and Pence would appoint a new VP....
...as I understand it from High School civics I took over fifty years ago.
Which means you are exponentially better informed than the current crop of intentionally dumbed down public HS graduates, (homeschoolers and private school graduates being the exception to that rule)
You are correct. I too, took Civics. I was simply being coy when I said ( non specific personage) “if something were to happen”