Originally Posted by nystateofmind

1) When you search, Delta puts cookies on your computer so if it sees you looking at a specific city pair on specific dates it will price it higher because it perceives that you are wanting to fly those days.

2) Unlike an airline like JetBlue, Delta's mileage award pricing is not tied to the paid fare. Delta has a certain number of mileage seats on each flight and that is out of a separate inventory.