Yes, it is possible for airlines to make changes to your flight times. By reconfirming your flights in advance of both your outbound and return flights you will be made aware of any possible changes.
Flights Ticket Gostrongly recommend that you reconfirm your flight times and status by calling the airline directly 24 hours prior to departure for international flights.
Some international airlines do require passengers to call and reconfirm their flights a certain number of days/hours prior to departure. If the airline does not receive re-confirmation from the passenger, the reservation may be cancelled.
If you are traveling on an airline that requires reconfirmation, we recommend that you call the airline to find out how far in advance you must reconfirm and any other applicable requirements the airline might have.