MXP to Bologna

A base fare ticket from Milano Centrale to Bologna Centrale is only 48 EUR for a 2nd class ticket and it is only a 1 1/4 hour ride. I suggest you just buy a ticket when you arrive at the MXP train station. Even with a direct flight, there are any number of reasons you could be delayed. Mechanical, weather, immigration, luggage.

Wait til you arrive to purchase tix-either at kiosk , window or on the app
Delays happen, no way to predict how long passport control will take

Use official train site
https://www.trenitalia.com/en.html

Since our flight is direct, I’m hoping delay is not probable.

You flying from EWR?

You flying at a time of year when weather might be an issue?

Pre-purchasing a ticket means you get to worry from then until the trip 'will I be on time'? You really want that stress?

Buy on the spot when you arrive. Assuming there are still discounted tickets for the date you arrive, at most you can save about 16€ or so. It's not worth the risk of losing everything if your plane arrives late and you miss the train you booked.

unAs suggested, you can purchase the tickets once you arrive at MPX and are past immigration. If you have downloaded the Trenitalia app and set it up with your credit card, you can purchase both legs of the trip in one quick transaction. You can also purchase from machines and ticket counters but in case there are lines, the app is quick and easy. Also, if you do purchase tickets in advance on the app, you can re-book if needed up until the time the train you initially reserved leaves the station. But as others explained, there is no advantage in booking in advance.

Listen to the advice. My daughters flight was delayed 3 hours last week due to storms in the US so delays happen. A friend was delayed due to a medical emergency prior to take off... 2 hours in March.

Thank you everyone...

Yes, leaving from EWR, although PHL is our closer airport. EWR works for NS using United Miles to MXP.

You all validated my concerns. We will wait until we land.