The airline industry is a bit of a mess (at least here in Europe), and we’ve seen everything from multiple-hour delays to complete cancellations < 24 hours before a flight due to a strike.
Our new rule is that if it takes 6 hours or less by train, we take the train every time. There tends to be more space, free Wi-Fi, a food car, cheaper, and fewer things going wrong. You also get to see the countryside as you travel to your destinations. You may also have the opportunity to extend a transfer in an intermediate location to spend time exploring. So before booking that flight between locations, check the local train options first.