There's a lot about Earth we don't know about. We're so worried about finding mysteries in outer space when the answers are probably right under our noses. We need to learn more about our planet and how the be stewards of the environment before we EVER think about populating other worlds.
The idea of those being landing strips is just ludicrous to me. If you can travel interstellar space you don't need a RUNWAY...LOL.
Wait....that mountain top is gone......just maybe "they" have some spaceship made to haul dirt and it NEEDS a runway cuz it so BIG and heavy...Hmm!?!?!