I've always been amazed at the number of people who seem to visualize Europe as a few major cities with all of the attractions with nothing but wasteland in between. So, I guess, for them, flying between major cities seems normal. However, they still tend to look only at the time and cost of their flights and seemingly ignore 1) the time and cost of getting to the airport, 2) the time it will take them at the airport before they can board their flight, 3) the time at the other end deplaning and finding ground transportation, and 4) the time and cost of getting to their destination.
Maybe, because of the places that their visualization of Europe leads them to stay, they expect there to be an airport within a short commute of where they are staying. But for some of us, this is not the case. Of the 39 places I've stayed in over the last 20 years, 85% of the time I've stayed in towns (29) with less then 20,000 inhabitants. I just find small towns to be the most interesting from a cultural standpoint. Almost all of these places have not been close to an airport; I think that maybe 2 were within 45 minutes of an airport. So for me, the lack of convenient airports makes flying very impractical.
Not only is there the travel time to and from the airports, but there is often a mismatch between the arrival time of public transportation and the departure time of the aircraft, so instead of arriving a minimum of 1½ hrs before flight time, you might have to arrive 1¾-2 hours early.
Case in point, 4 years ago I went from St Goar to a town in the Ostallgäu, fairly close to Füssen. The time for the train was a little less than 6½ hours. I traveled with my partner on a Sparpreis ticket with seat reservations. Today, the trip would cost 55,80€ for the two of us.
The only airports I could have used were FRA and MUC. It takes 1½ hours to get from St Goar to FRA. Then add 1½ hours for checkin, security, and boarding, and you have to leave St Goar a minimum of 3 hours before flight time. The flight actually is only scheduled for 55 minutes. On the arrival end, it will take at least 30 minutes to get off of the aircraft, out of the terminal and over to the S-Bahn station to go to the Hbf, from which you catch a series of trains to the town in the Allgäu. That journey, from FRA to the Allgäu takes 3H19. Time wasted at airports due to the mismatch between surface transportation and flight time eats up another 60 minutes.
So the trip "by air" from St Goar to the Allgäu takes about 8½ hours, two hours longer than by train, even thought the flight itself only takes 55 minutes. And, the cost of airfare plus getting to FRA and MUC to my destination would be 250€ including a shared Bayern-Ticket for the Bavarian train connection.