Starting in the next few days, the Google Assistant on Android and iOS will be able to check in on your flights. Currently, you can only use this feature for domestic flights on United Airlines, but the promise is to expand this to other airlines over time. To try, you just say "Hello Google, check in to my flight" and by you, ready to enjoy your stroopwafel as you board.
The assistant will go through the check-in process, so it's not all 100 percent automatic, but it still looks like a good user experience overall. However, if you are about to be in control, change your locations and check the status of your upgrades, it is likely that you still want to keep up with the airline's own app.
In addition, in order to check in on your flights, the assistant can now book hotels for you. To do this, Google has partnered with Choice Hotels, AccorHotels, InterContinental Hotels Group, Priceline, Mirai and Travelclick. To do that you already need to know where you want to live and which hotel you want to book, so I am never quite sure how good such a function really is in daily life. If you regularly stay at the same hotel on every trip, and may not care about shopping, I think this can save a few clicks.