This video gives you a little bit of a look behind the scenes:
The production used drones from this company, the frames and gimbals of which start at about $2000:
Assuming (safely) that this was shot with DSLRs and a reasonably small set of lenses, we're probably looking at less than $10,000 in total equipment cost.
A few years ago these shots would have required a full crew, a helicopter and a mobile crane; today, you can just order a drone from a hobby site and, with a little bit of practice, film them yourself.