If you use a travel agency to book your travel, make sure you are aware of the "shift share" strategy.

Basically, the travel agents have a hard time making money selling airfare.  Airlines stopped giving commissions in the early 2000's, but some travel agents have special agreements with certain airlines.  In order to make more money, travel agents try to shift a share of their customers to the airline where they get some commissions.

This means that sometimes travel agents are trying to sell you certain flights based on where they get the best commission instead of basing the flight on where you will pay the least and have the most direct flight.

I always knew that travel agents did this when they sold cruises and vacation packages, but I didn't realize they also do this with flights.

The best way to counter this sales strategy is to do your own airfare research.  It is really easy to use one of the online airfare search engines to compare flight options.  No matter how well your travel agent sells you on a certain flight option, always do your own research to figure out if you are getting the best deal or if you are being share shifted.