Q. I’m researching tickets from Seattle to London for travel at the beginning of April. I've found that the same plane (same time, flight number flown by British Air) leaves under three different airline names with fares from $719 (Iberia which breaks down to $270 plus $449 taxes and fees) to $1247 (American, $1050 plus $197 taxes and fees). What's going on here?  I've looked at Cheaptickets.com, Expedia and Priceline.

A. What you’re seeing here is a code share situation. British Airways has a marketing agreement with American and Iberia, both of which buy seats on British Airways and are free to sell them for whatever they wish. The flight is being flown by British Airways. This is one reason why online travel agencies are so important. Had you researched the flight on AmericanAirlines.com, you would only have seen the higher $1247 fare on American. Sites like Expedia show you all the possibilities. On another travel date, it’s possible that American would have had cheaper seats than British Airways (by the way, for the time being, Expedia is no longer listing American’s fares, nor does Orbitz, which owns Cheaptickets.com). So just buy the cheapest fare. It’s the same flight, same airline, same service no matter how much or little you pay.