03/27/2010 05:12 am ET Updated May 25, 2011

The Sky Is Falling: How Safe Is Flying in the US vs. Abroad?

It hasn't been a good 48 hours for international air travelers. First, a Russian-made passenger plane crashed in heavy fog in Mashhad, Iran with 170 people on board, injuring at least 46. Then an Ethiopian 737 with 90 on board went missing after taking off from Beirut, Lebanon. There appear to be no survivors.

Both crashes underscore one of the fundamental facts about aviation safety: Your safety depends on where you're flying. In other words, commercial jet travel in the domestic United States is safer than most places on earth, especially the developing world.

Arnold Barnett is a professor at MIT and leading authority on aviation safety. To get to the bottom line for those afraid of flying, he created a statistic known as Q. It measures your risk of death on your next flight. (Barnett, it should be noted, is afraid of flying.)

Despite the latest crashes, Barnett says, commercial jet travel is actually getting safer. For the purposes of understanding risks, he divides the world and its airline carriers into different categories.

For instance, he argues, your risk of dying on your next domestic jet flight in the United Sates is one in 60 million (based on data from 2000 to 2009). In other words, you could fly every day for the next 164,000 years on average before you would perish in a crash. For the purposes of comparison, Barnett estimates that your risk of dying in your next car ride to the grocery store is around one in nine million.

Back to air travel. If you fly domestically by jet in the rest of the industrialized world (say, Europe), your chances of dying -- one in 30 million -- are worse than in the US. Barnett notes that the difference is "statistically unreliable" given that both risk numbers are based on "exceedingly few fatal events."

If you travel between countries on First World carriers, your risk of dying increases. In this case, Barnett says, your Q is about one in 10 million. And if you fly on Third-World or former Soviet bloc air carriers, your risk of dying is about one in 2 million.

In short, if you fly in the United States or the major industrialized nations on First World air carriers, your chances of perishing are incredibly slim. If you fly outside the US on non-First World carriers, the risk is still extremely small, but not as negligible.