I’m deducing that during the intervening 70000000 years that the laws of physics that effect aerodynamics, lift and air density have changed significantly, too.
I'm guessing that the shallow ocean Chixulube strike created a magma powered rocket engine 120 miles across that blasted a significant fraction of the Cretaceous atmosphere into space.
The only things that survived were burrow dwellers that we accustomed to oxygen depleted tunnels.
I seriously doubt that any of the laws of physics changed at all, especially since a relatively recent time as 70 million years ago. Perhaps on the grand scale there could conceivably have been some, at least minor, changes in the value of the physical constants, such as the gravitational constant, or Hubble 'Constant', which is the rate the universe is believed to be expanding.
In fact, that rate definitely appears to have changed (dramatically) over the course of the life of the universe, from the Big Bang to modern times.
According to the Inflationary Big Bang theory, the most accepted today, the rate was insanely high at the start, many times faster than light. Then, for some reason, the rate slowed tremendously, then started speeding up again!