Airlines have different types of aircraft in their fleets, which, in addition to technical characteristics, also differ in capacity. Clearly, this allows companies some flexibility in the market, here is our explanation in details.
For example, Croatia Airlines has 3 different types of aircraft in its fleet:
DashQ400 with 76 seats,
Airbus A319 with 144 seats,
Airbus A320 with 184 seats.
For comparison, Austrian Airlines has 7 different types of aircraft in its fleet:
Dash Q400 with 76 seats,
Embraer 195 with 120 seats,
A319 with 138 seats,
A320 with 174 seats,
A321 with 200 seats,
B767-300ER with 211 seats,
B777-200ER with 306 seats.
It is very clear that Austrian Airlines in the market can be even more flexible compared to Croatia Airlines in terms of fleet diversity and capacity. But do companies change the type of aircraft on certain routes? The answer is yes. Sometimes this is in the long-term plan of the airline, for example, it is very clear that on a certain route the demand will vary depending on the day of the week, so they will plan the capacity on the route according to that as well. Changes also occur depending on the flight schedule, whether it is a winter or summer schedule, of course, the number of seats offered is higher in summer compared to winter. But ad hoc changes happen every day, and the reasons are numerous:
AOG of the planned aircraft, there is no same type available, sending a larger or smaller aircraft on the line,
Operational changes, the aircraft will not return from the destination where it operates on time and is planned for another route to which it must go due to daily or multi-day rotation,
Crew availability (lack of cabin or flight crew for a particular type of aircraft),
Drastic change in booking (last minute reservations),
Regular and extraordinary inspections on a certain type of aircraft, etc.
Realistically, on flights within Europe as passengers should have no problem if there is a change in the type of aircraft. Passengers very often do not even notice it, only those who fly very often and are lovers of aviation will notice such a change.
The problem for almost every passenger arises when he makes an online check-in a day or more before the flight (depending on how early the airline allows it for passengers), chooses the seat that suits him best, if traveling with someone he choose a seat next to each other, and then when they arrive at the airport when they check-in for the flight they get a boarding pass with completely different seats. Why? If the passenger has already checked in for the flight online and there has been a change in the type of aircraft, the system will automatically assign a new seat to all passengers and the chances of it being the one the passenger has previously chosen are very small. All you have to do is ask the airport staff at check-in to change your seat. If the flight is not completely full, the agents should do it for you without any problems.
When traveling on a direct flight that lasts longer than flights within Europe (to Asia, North America, etc.), it is important for most passengers to get the seat they prefer (to window, aisle, etc.), while on the other hand airlines often present their service in airplanes like a variety of entertainment content on the screens in the seat in front of you, a good seat peach, a cabin configuration that is always important to people traveling in pairs and thus actually want to attract passengers. But when there is a change of aircraft on the route for any of the previously mentioned reasons, companies sometime use aircraft without mentioned benefits for passengers.
You may, for example, pay in advance for a first-row economy class seat or an emergency row (yes, companies generally charge for this). You were not sorry to give a few euros to make your long flight more comfortable and to have better legroom. On the day of the flight, the company changed the type of aircraft and assigned you the same seat number that you choose, except that in the replacement aircraft it is no longer the first row or emergency row, in front of you there are two more rows of seats to the first row or emergency exit. What to do? Try to contact the company, mostly in that case they do not have too many options but at least you are entitled to a refund.
Also, many large and well-known companies have a policy that many travelers do not know, it is stated in those small letters that, let's be honest, we do not read. For example, if you travel by Emirates or Korean Air from Zagreb to Dubai or Seoul and the plane does not have operational screen in the seat (it happens, sometimes one, sometimes more of them not working, rarely but it happens that due to a technical malfunction none of the screen works - we know about one case from Zagreb where the flight lasts over 8 hours) you have the right to claim the airline because they did not provide you with the service which they advertise and offers. Depending on the kind of denial of service in question (the mentioned screen failure in the seat, non-removable seat, the non-functional handle, etc.), many companies compensate for such failures to the passengers. We believe that you have not heard of this yet, but those companies for which customer service is important really do it.
Also, pay attention to the configuration of the aircraft. It is based on 2-2 or 3-3 on narrow-body aircraft, which we mostly travel on routes within Europe, and there are not too many surprises, while the configuration of aircraft operating on long-haul routes is mostly 2-4-2 or 3-3-3, but there are of course other versions as well.
In conclusion, we can say that changing the type (capacity, configuration) of the aircraft on one route is nothing strange or rare. The change can be planned and as such will not create a problem for either the passengers or the airline, while the extraordinary ones can harm both in a certain way.