<=3 hour flight time kind of sucks, because you're spending additional 1-2 hours at the departure airport and at least 30 minutes at the arrival airport. Then there are the trips from and to airport which are often 1-2h. Then there's scheduling slack, which translates to additional ~20% wait time. When flight time is 3h, you're expecting to spend 7-12 hours. Usually closer to 12, because you'd rather wait longer than run the risk of missing one of the transports.

One of my great travel-related discoveries has been that if I can find a train that takes even about the same amount of time, it will always be much more pleasant and less energy-draining than air travel.