Would setting up and using a VPN (Virtual Private Network)increase security when using "public" wi-fi networks, like in airport lounges or when using local ISP's when traveling overseas (e.g. using a local sim card in my phone to get internet)

I just got back from an extended trip in Eastern Europe, and these security issues were a bit of concern. I know nothing about VPNs other than they exist and that they claim to 1) increase security and 2) get by internet blocking (e.g. would have let me watch Netflix while sitting in an airport lounge for 6 hours)