The CW, guys who brought us Smallville (Live-action Superman origin story), brings us a huge crossover event Heroes vs Aliens. It includes Green Arrow, The Flash, etc. and Supergirl. They make reference to World War Z and Star Trek, I see what you did there. Though the aliens look a bit cliche. Also, they keep showing the aliens take a beating, but it a select number of heroes vs an army of aliens.
See Heroes v Aliens on the 4 night crossover event, starting with Supergirl Monday at 8/7c on The CW!