Just read today that they are releasing many weather balloons across the country at 30,000'. The added purpose is that a box will be fitted to allow broadband transmissions to take place.
The question is 'are they dangerous to aircraft where they could be sucked into the engine and cause a malfunction'?
No, they will fly at 100,000 feet.
The comical thing is that they will last for only 24 hours and will therefore have to be replaced daily, with a daily search for their dropped kit.