The age of the PWA is here, and since Google is unlikely to ever make many native Windows apps, it is to the PWA that we have to look for Google apps and services.
Google Travel, which consolidates Google Flights, Hotel Search, and Trip, is now available as a PWA on both phone and PC.
When you visit google.com/travel Chrome will now offer to Install the application, resulting in a shortcut being placed on your desktop (or phone home screen) with a custom icon.
The PWA is not terribly advanced, without any apparent off-line capabilities, but does offer faster access to your Trips and more. It does, however, offer support for notifications related to your planned itinerary and which will open in the app.
Google had earlier killed a native Google Travel app which offered more features, including offline maps and itineraries. Hopefully, the PWA will eventually catch up with this.
To get Google Travel on your desktop visit google.com/travel and click the Install + in the address bar.