Q. I was denied boarding on a flight to Brazil because, although my passport was valid and didn’t expire until several weeks after my return to the U.S., the airline informed me that many countries require that a passport be valid for six or more months from the time the passenger returns home. This doesn’t make sense to me. Do other countries have similar policies?

A. Unfortunately, a number of countries have similar requirements, so it’s essential that, when you fly to a foreign country, you research passport validity period requirements. Airlines are not required to inform you of these rules when you book your seat. Make sure you learn about required visas as well.