I live near the Aberdeen Proving Ground in Maryland. They are doing a multi-year test of two tethered Aerostats that are almost 250 ft. long. Apparently they are an early warning system for missile launches inbound.
The system is outrageously expensive and dependent on the weather.
They fly at a constant 10,000 ft. My son goes to school about 50 miles away and he can see them from a local Walmart parking lot.
So I just saw a tweet that the Aerostat I mention just came loose from its tether. They apparently don’t know where $200,000,000 just flew off to.