Ten years ago, the decision to drive or fly was usually pretty simple. Airfares were cheap, relatively speaking, and it seemed like multiple carriers flew the same route, adding to the convenience of flying.

Today, things have changed. Post 9/11 security hassles aside, flying has become expensive and inconvenient, with fewer carriers, fewer direct flights and a lot more passengers to contend with.

It can be a tough call deciding between flying and driving these days, assuming you can spare the time to get from point A to point B by car. If you want to compare the financial burden of flying versus driving, Inside Line says the Cost2Drive app, available for iPhone only, may be just what you’re looking for.

It’s simple enough to use: just plug in your point of origin and your destination, followed by the vehicle you’ll be driving, and the app calculates the driving distance, the time it will take and the proposed route. It gives you an estimate on one-way airfares, and even  calculates your carbon footprint while allowing you to buy carbon credits.

If there’s a downside, it’s that the app costs $1.99 and still relies on the Cost2Drive website for directions and routing via MapQuest, Google Maps or Yahoo Maps. Sure, it gives you nice details like where to stop for gas along the way (assuming you drive the posted speed limit and achieve the estimated fuel economy), but your fuel gauge or trip odometer does the same thing.

Call us cheap, but we’d probably opt to use the slightly-less-convenient-but-free Cost2Drive website for trip planning, backed up by the navigation program of our choice.