WP Travel requires authentication to access the API. It is possible to authenticate using the user name and user application password.
How to generate the Application key.
To generate the key first you need to generate the user application password. for that go to Dashboard >> Users. Then edit the user for whom you want to create key
Scroll down the page, you will see the Application Password option. From there you will able to create an application password
After this step, you will get the application key. Now you are ready to generate the key.
You can simply convert the combination of username and user application key to generate the key. For that, you can encode “username:application-password” in base-64
Or go to https://www.base64encode.org/ to generate key