To enable flying on a Minecraft Spigot server, you need to do two things: update the server's configuration files and give players the appropriate permissions.

Here is a step-by-step guide:

Update the server.properties file

1. Locate the server.properties file in the root directory of your Spigot server.

2. Open the file with a text editor such as Notepad++ or Atom.

3. Locate the line that starts with "allow-flight=" and change the value from "false" to "true".

4. Save the changes and close the file.

Grant the players permission to fly:

1. To grant flight permission to all players, install a permission plugin like LuckPerms or PermissionsEx if you haven't already. You can download these plugins from the SpigotMC website and add them to the "plugins" folder in your server directory.

2. Once the plugin is installed, you need to configure it. Locate the plugin's configuration file (usually called "config.yml") in the "plugins" folder, in a subfolder with the plugin's name.

3. Open the configuration file and add the necessary permissions for flying. For example, for LuckPerms, add the following permissions for the appropriate group or player:

- essentials.fly: allows the players to switch the flight mode

- essentials.fly.safelogin: allows players to log in when flying

4. Save the changes and close the file.

5. Reload or restart the server.

Test flying in the game

1. Log in to your server and use the "/fly" command (provided by the Essentials plugin) to enable or disable flight mode.

Now players with the appropriate permissions should be able to fly on your Spigot Minecraft server. Keep in mind that allowing flying may increase the risk of cheating or exploiting, so consider using additional anti-cheat plugins to ensure a fair gaming experience.