One way is tho go on the airport's site and look at their incoming flights on the weekday and in the 0-3 hours before the scheduled departure of your. Look for any incoming flight that has the same alphabetic prefix as yours. However, this is not a useful way, nor will you really ever know for certain, when your departure airport is your airline's hub or at least it has more than one flights coming in and going out at about the same time (BA at Heathrow comes to mind). The airline may easily switch aircraft around if there is a delay somewhere in the chain and you might benefit by an aircraft that was intended to go elsewhere will now be allocated to your flight. On the other hand, the one that was there, available and intended for your flight, might be switched to serve another route because they want to give it priority.