I don't believe extraterrestrial spacecraft have ever visited Earth.
I'm not aware of any instance where extraterrestrial technology was used in an aircraft or to push the envelope for military flight technology.
In fact, much of it has a publicly-traceable lineage, if people would just dig. I'm thinking of low observability (stealth) technology, the latest RADAR/LIDAR tech, airframe designs, ram/pulse/pulse detonation jets, and so on. I admit some of it looks like magic on first glance, but this stuff was designed by human beings who were much smarter than me.
I'm not aware of any instance where extraterrestrial technology was used in an aircraft or to push the envelope for military flight technology.
In fact, much of it has a publicly-traceable lineage, if people would just dig. I'm thinking of low observability (stealth) technology, the latest RADAR/LIDAR tech, airframe designs, ram/pulse/pulse detonation jets, and so on. I admit some of it looks like magic on first glance, but this stuff was designed by human beings who were much smarter than me.