Hello,
Thanks for your email!
Actually, we are sorry to say that WP Travel plugin is not compatible with Polylang however, worry not it has already been noted as a Feature Request so we will work on it in our near future.
Also, if you are willing to translate the tabs then worry not, the strings that are used in tabs cannot be translated as the strings for tab are editable and not hardcoded. So, you have to add a translated string for the tab manually.
For detail assistance regarding regarding translating tabs in single trip page, please once refer below-given link:
https://wptravel.io/how-can-i-translate-tabs-in-single-trip-page/
Further, WP Travel plugin is compatible with the WPML plugin as using the WPML translation plugin, you will be able to display your site in multiple languages.
For detail assistance, please refer to the below-given link:
https://wptravel.io/is-it-possible-to-display-the-website-in-multiple-languages/
If you have any queries further, feel free to contact us.