You can measure your luggage and see if it meets the requirements for a particular airline.
If you don't see the "Baggage" widget that means we don't have the baggage requirements for that airline yet.
Not all model devices support the augmented reality (iPhone 6S and above do support). For Android, it varies depending on the particular model.
Go to your Trips → Select the flight
Scroll down and click on the "Baggage" widget
Then you should tap on the "Measure" button
It will take you to the camera mode where you can compare your luggage with a virtual version of the requirements size carry-on / drop-off luggage
Go to your "Trips" → Select the flight → Find the "Baggage" widget → Tap on "AR"
Then you will be able to compare your carry-on / drop-off luggage.