If you hear this from a representative of an airline in the counter of any airport…. run !!! Run to the check-in area and talk to the rep there. Let me explain. Suppose that you are in any of the airports in the United States. Hopefully you are booked in one of the earliest flights and this first segment will take you to one of the main hubs (Houston, Chicago, LA, Miami, or New York) where you will take a connecting flight to Peru or any other far and exiting country you decided to try for your vacation.
So you made to the airport, waited in line to check your bags and are now sitting comfortably, maybe eating a burger or a salad, waiting for boarding. All of the sudden the rep in the counter announces that the flight will be delayed a bit. Okay, no big deal, so you keep eating. An hour later the rep makes the following announcement to the now ‘tired of waiting’ crowd: “the plane has been delayed because of some repairs, please have some patience, I will update you in an hour”. At this point there are only two outcomes: One, the mechanics do fix the plane in time and now you will have the chance to flight on a plane that hopefully was fixed correctly or after an hour a second announcement, something like this: “We had been informed that they are waiting for a part that will arrive in X hours”.
That is your cue to drop the sandwich and go to the check-in counters and change your flight plans. I know what you are thinking. You are an optimist. Maybe the part will arrive in time and then the pilot will burn all the extra fuel to make up the time and I will arrive at my destination on time. Sure. But this is what is going to happen. They might or might not get the part on time, if they say is 2 hours then is probably really 3 hours until they get the part. By that time so many people had changed flights that the flight is no longer profitable for the company. That is the same reason why the pilot will not fly at full speed. Burning the extra oil makes the flight not profitable anymore. And when all of that happens guess what the airline is going to do… Yes, they will cancel the flight.