You can book flights almost a year ahead of time but the actual airport slots are only confirmed 3 or 4 months before the flight, so they are in effect provisional until that point. There can be changes in aircraft type and other issues that affect the assignment of timeslots and routes, some of which can be unpredictable, so it's not always the airlines trying to make a quick buck.
Between us we fly over 60 flights a year, a mix of Aer Lingus, Ryanair, BA, and American Airlines. American is the worst for random flight changes, although usually just by a couple of hours. Happens maybe 1 in 5 trips.
BA is next, happens me about 1 in 10 trips. Recently they cancelled my flight 15 days beforehand and switch me to one 5 hours later - customer service said it was due to low numbers on the original flight so they repositioned that plane to another route. They can't afford to fly an A320 with only 30 people on board.
Aer Lingus are generally OK, changing maybe 1 in 20 or less often. I was recently stuck in an airport for 10 hours due to Aer Lingus constantly delaying and then eventually cancelling a flight, but when you start to look at the logistics of commercial airlines it's actually a miracle they are as reliable and efficient as they are.
There are many pros and cons to Ryanair (and they are not my 1st choice) but they are actually the least likely to change in my experience. Where they seem to have fallen down here is the lack of communication, but they are not the only ones.
Between us we fly over 60 flights a year, a mix of Aer Lingus, Ryanair, BA, and American Airlines. American is the worst for random flight changes, although usually just by a couple of hours. Happens maybe 1 in 5 trips.
BA is next, happens me about 1 in 10 trips. Recently they cancelled my flight 15 days beforehand and switch me to one 5 hours later - customer service said it was due to low numbers on the original flight so they repositioned that plane to another route. They can't afford to fly an A320 with only 30 people on board.
Aer Lingus are generally OK, changing maybe 1 in 20 or less often. I was recently stuck in an airport for 10 hours due to Aer Lingus constantly delaying and then eventually cancelling a flight, but when you start to look at the logistics of commercial airlines it's actually a miracle they are as reliable and efficient as they are.
There are many pros and cons to Ryanair (and they are not my 1st choice) but they are actually the least likely to change in my experience. Where they seem to have fallen down here is the lack of communication, but they are not the only ones.