Here's a quick tip to get the fastest speed: Don't move around.
That's right, this might sound irrelevant but it's not. The vast majority of airports have a large Wi-Fi network, called a mesh network, composed of many . Think of them as little Wi-Fi satellites that carry a portion of the airport's router's signal. When you first connect to Wi-Fi at the airport, you'll likely connect to the access point that gives out the best signal at your current location. If you walk into a new area, farther away from the access point you're connected to, your device won't necessarily switch you to a new, closer access point. This translates to slow speed and even disconnection.
So, when you have to move from one place to another, even just a few feet apart, if you feel your internet experience has clearly slowed down, it's best to re-establish your connection. It's easy: Just turn on airplane mode on your device for a few seconds, then turn it off. Your device will now look for the best access point based on your current location. And then, again, stop moving around when you don't need to.