[Reubend]

Sure, what's preposterous about that?

We can't assume that getting "help" is trivial just due to the volume of travel. Commercial airplanes can't rescue each other, just as an example.

I don't believe that aliens are making contact with Earth. But I don't find your argument against that possibility convincing either.

In my mind, a much better argument would simply be that with 7 billion people on this planet, the likelihood of alien crashes staying secret seems miniscule. We would have solid conclusive evidence already if it had happened multiple times, like alledged.