If an advanced alien civilization has technology allowing interstellar travel, they also have weapons that would make shooting a missile at them from a fighter plane as futile and self-destructive as throwing a rock at a battleship.
-ccm
Your assumptions seem to be greatly flawed . . .
though our missiles against them have been largely ineffective due to their advanced tech.
Reportedly they were not quite prepared for some of our radar installations and their effects on the UFO craft when Roswell happened.
They reportedly adjusted their stuff and didn’t have THAT specific problem again.
Besides . . . technology is never flawlessly perfect in all unforseen contingencies . . . even ET technology.
More than that, they would also have technology that would make it absolutely unneccessary to enter the atmosphere to find out whatever they wanted to know about us.
Then there’s the fact that they would find us less amusing than watching paint dry.