You can check your emailed itinerary to find out which airline you are flying with. You can also find out by checking on the mySTA app*
In some cases, your flight may be operated by another airline. This is called a ‘codeshare’.
If you are travelling on a codeshare flight you will need to go to the desk of the aircraft which is operating the flight. For example, if you have a Qantas flight from London-Melbourne but it is 'operated' by Emirates you will need to go to the Emirates check-in desk.
*Some of your low cost carrier flights e.g easyJet, AirAsia etc. may not appear on your account online. To check these flights please refer to your latest itinerary.