Airfares Flights How Come Airfares And Availability Varies?

How come airfares and availability varies? - airfares flights

I am so aggravated! We booked non-stop flight and had cost more one-way flight, 97.00. So we went with the flight no longer and it is much cheaper. Then I checked today and suddenly the non-stop flight is available again and 102.00! It is too late to change now, because we already paid for the others, but what happened? Why are airline tickets and flights varies each day? I should mention that the journey we make, not for 3 months, it is not like a last minute thing. I'm sure po'd!