I think y'all guys are under a slight misunderstanding.
Yes, its true that if these are ships from outside of our space system (just to make it reasonable), it does not mean that those ships aren't still subjected to physics.
Once a ship of that type comes to Earth, it now has to deal with local phenomena, such as atmosphere, weather, etc.
Didn't the Roswell ship get brought down by lightning? A missile can easily bring one down.
The ship is still subjected to our laws of physics until they alter the environment.
Also, nothing can go faster than the speed of light. You would have to warp spacetime.
So, these ships are 1) homemade with advanced technology, 2) interdimensional, phasing in & out of our dimension, 3) interplanetary, able to find, use & survive space, black holes, "wormholes" & much much more.
1 is reasonable, 2 will alter mankind & 3 is the scariest.