This post is about trying to get a sense of how and when to best use your miles for reward flights. Here miles are compared to the cost of the flight to try and obtain a kind of correlation of how many miles are needed for a certain flight. The comparisons are shown below.

For this analysis, Delta Skymiles was chosen as the rewards program, and the flight that was chosen was a one-way ticket from Chicago to Dublin, Ireland.

Overall Comparison
Here is a a very basic day-to-day comparison of flight cost vs. reward miles cost. This comparison is over a span of 331 days from June 1st, 2015 to April 26th, 2016. The prices for the flights were taken on June 1st, 2015.

 Below, a running average of 25 data points for the the miles and money were graphed:

As observed in the graph, a trend of downwards cost also results in a downward cost in miles per trip. Also, that reward travel is more volatile in cost and tends to cost more during certain holidays. Below, is a direct comparison between flight cost and mile cost where the bubbles are weighted in size by frequency of the miles cost:

A slight relationship can be seen between the cost of flight in dollars to a direct relationship to a cost of flight in miles. It is also noted that the most frequent cost in miles for a flight was the most expensive mile cost tier at 65,000 and the second most at the lowest mile cost tear at 30,000 miles. Finally the cost of miles were broken day by day to search for any intraday effects.

Thursday, Friday, and Saturday, were shown to be on average the most expensive days for mileage rewards while Monday, Tuesday, and Wednesday were shown to be the least expensive on average.