Once you've completed your booking in Hopper, you'll receive an email confirmation with all of your trip details. You can also view your upcoming and past bookings directly in the app! If you tap on one of your trips, you'll see:
Travelers booked on the trip
Good to know
iOS and Android interfaces slightly vary.
If you're on Android, your upcoming and past trips can be found under the "Trips" tab at the bottom on the screen:
If you're on iOS, your upcoming trips will be located on the main screen, while past trips can be found under your settings
Any changes to your booking made directly through the airline will not be reflected in the Hopper app.