How about dig a big hole at the end of the runway. Plane lands, falls in the hole, the locals quickly and quietly fill it back up, smooth it over then go about their day like nothing happened. A plane landed? Nope, never saw anything.

We’d know. They’d know that we know. But no one says it out loud. Kinda like how the world knows that Trump is a dangerous moron but no world leader actually comes out and says it.