Airfares 
(A webquest for grades 9-12)
 

Introduction:

More and more, flying is the way to travel.  But if you do not plan ahead, that convenient flight could cost a lot more than you origionally thought.  In this webquest, you will investigate the relationship between how early you purchase your tickets and how much the flight actually costs.

Task:

Using Internet resources, you will obtain the costs for flying to at least six different cities.  You will also obtain the different costs based on how far in advance you purchase the tickets.  Assuming a linear relationship, you will develop a model to predict the cost of a ticket to a particular city.  You will review this model and as a team, conclude whether you think it is a good model or not.

Resources:
 

American Airlines: http://www.aa.com
British Airways:  http://www.britishairways.com
Continental Airlines:  http://www.continental.com
Delta Airlines:  http://www.delta-air.com
 

Process:
 

1. For each airline, pick a different city to visit.  Find the cost of a roundtrip flight from Charlotte to that city, leaving in two days, a week, two weeks, three weeks, a month, two months, and three months.
2. For each of th four trips, make a plot of "days until departure" vs. cost of flight.  Do you think there is a linear relationship in any or all of these?
3. Pick one trip that your team feels has the most linear relationship.  Find the equation of the line of best fit (depending on the class here and what had been taught so far we could use the calculator or do it by hand.)
4. Using the equation, predict the cost of a roundtrip flight leaving in 1 day, 10 days, and 100 days.  Go back to that airline website and find the actual cost in each of the three conditions.  How accurate were your predictions?
5. Discuss with your team whether a linear model is best for the data that you collected.  Give at least two reasons to support your answer.

Conclusion:

In this activity, you used the internet to collect data and determine if there was a linear relationship.  You assumed that relationship and used a model to make predictions.  You used your reasoning skills to analyze that model and determine if it was valid or not.

(Note:  Upon concluding this activity, I would introduce the concept of exponential functions, which best model this data.  Depending on the course objectives, I would expand this lesson to have students develop an exponential model here.)