[madeofpalk]

It’s next to impossible to actually answer this precisely at any time 3 hours before departure for airlines that fly both Airbus and Boeing.

There will be specific planes scheduled for the flight in advanced, but it changes frequently up until departure due to regular airline logistics.

[aero142]

Adding a date of travel and checking the scheduled tail number would be much more accurate.

[madeofpalk]

Kind of. The 'scheduled tail number' will change multiple times in the days before a flight.