I'm not sure why but some airlines are bad at informing passengers of changes to the schedules affecting bookings made but not flown. Earlier this year I had a flight cancelled by Lufthansa which I only found out when turning up for check in. The latest one was a significant schedule change by Qantas affecting several bookings by up to 4 hours. Fortunately I found out quickly and so was able to tune the bookings more to my liking. Had I left it until closer to departure there may not have been availability to make changes and I may have been stuck with the default.
With over 100 flights booked but unflown, schedule changes are bound to happen. I probably should pay more attention than I do. Ideally the airlines would send alert emails every time. The next easiest way to check schedule changes is to log on to the airline website and review your bookings. Some airline websites are good at showing all the bookings and even highlighting changes (usually with a message please contact the airline), while others are not so good.
For example Qantas shows all bookings associated with your Qantas frequent flyer number, regardless of where you made the booking and highlights the changes - that's good. However, credit your airline mileage to another FFP (frequent flyer program) and the flights are not shown.
Singapore Airlines shows all bookings (this is a fairly recent change - they used to only show bookings made online) but doesn't seem to highlight changes at all. Some of the "manage my booking" functions you'd expect also only work on bookings made online.
Air New Zealand is the opposite extreme with very limited functionality. Not only are bookings not displayed, but you have to enter the record locator (6 character booking reference) and your email address and phone number. Even then it only works for bookings made online. They have a long way to go to match best practice!
Fortunately you don't need to rely on airline websites to check your bookings. Some online travel agents will show all your bookings made through them, and highlight changes. Zuji is an example of this. Also each CRS (computerised reservation system), sometimes also called GDS (global distribution system) but I'll keep it simple by referring to as CRS here, has an associated website where you can check bookings made with airlines who use that CRS - as long as you know the record locator and your name.
So which CRS do I need to check you may ask? While they are interconnected it is best to look up the home or native CRS of the airline you are flying. This will have the most up to date and complete information. So on itineraries involving multiple airlines you may need to check more than one system - even though you might see all the flights on the first CRS you check, the information may not be correct.
For a selection of airlines, here is the native CRS.
- Amadeus (Check My Trip) - Air France, Iberia, Lufthansa, SAS, Continental, America West, British Airways, Qantas, South African Airways, (Opodo), (Expedia)
- Apollo/Galilio (View Trip) - United, Aer Lingus, Air Canada, Alitalia, KLM, TAP Portugal, (CheapTickets)
- Sabre (Virtually There) - American Airlines, All Nippon Airways (ANA), Cathay Pacific Airways, China Airlines, Singapore Airlines, Dragonair, EVA Airways, Garuda Indonesia, Malaysia Airlines, Pakistan International Airlines, Philippine Airlines, Royal Brunei Airlines, Silkair, (Travelocity), US Airways, American Trans Air (ATA), Midwest Airlines, Hawaiian Airlines, Alaska Airlines, Air Malta, Frontier Airlines, Aeroflot, (Expedia)
- Worldspan (My Trip and More) - Delta, Northwest, (Expedia), (Orbitz), (Hotwire), (Priceline), Swiss
Note, however, that some airlines have their own CRS with no way for the public to view bookings (other than on the airline's website where available) - eg Air New Zealand.