The article mentions it does show up on radar. But it also depends on the altitude it's flying at. The friendly European airforce must have been sleeping becau

The article mentions it does show up on radar. But it also depends on the altitude it's flying at. The friendly European airforce must have been sleeping because the article never mentions any attempted investigations or interceptions by the same. I imagine just like the US in 9-11, they'd be caught with their pants down if terrorists actually tried to use a fleet of these things.