I can't see how I can respond to other answers so I will make another answer to respond to Jon T. Sorry Jon, that is incorrect. I bought a Dell XPS 15, not a Macbook Air. The Dell uses Thunderbolt 3, not USB 3.1 like the macbook. It just uses the USB-C connector as per the thunderbolt 3 specification. According to the thunderbolt website, Thunderbolt 3 (using USB-C) is fully backward compatible with Thunderbolt 2 (Apple stuff) with an adapter. I just need help finding an adapter.
See this page for more information: https://thunderbolttechnology.net/tech/faq