> The fact that people think we could easily shoot down alien craft is slightly concerning.
It's not obvious that aliens who reach Earth must be much more technologically advanced than we are. They could have come here in a generation ship, which probably only requires builders who are a little ahead of us, and that only in fields like bioengineering.
For most of what they'd need for a generation ship our current level of technology is fine. In particular there is no reason they would have to be better than us at aircraft or weapons technology, so whatever vehicles they bring along to use when they want to enter a planet's atmosphere might be no better than what our current air forces have.
It's not obvious that aliens who reach Earth must be much more technologically advanced than we are. They could have come here in a generation ship, which probably only requires builders who are a little ahead of us, and that only in fields like bioengineering.
For most of what they'd need for a generation ship our current level of technology is fine. In particular there is no reason they would have to be better than us at aircraft or weapons technology, so whatever vehicles they bring along to use when they want to enter a planet's atmosphere might be no better than what our current air forces have.