Gone are the days when travelers could use an original birth certificate and a driver’s license to fly over the U.S. borders with Mexico and Canada. Secure documents, such as a passport or identification issued by the U.S. Customs and Border Protection’s Trusted Traveler program are now the norm. Spur of the moment flights to neighboring countries are still possible, but you’ll need to have the right documentation.

Acceptable Forms of Identification for Flying to Mexico and Canada

A U.S. passport book is universally recognized by customs agents in Canada and Mexico. If you’ve never had a passport, fill out the form online or head to a passport agency to apply. You’ll need to be able to prove identity with a valid form of ID like a driver’s license and also prove U.S. citizenship with an original birth certificate or naturalization papers. Standard processing time is four to six weeks. Passport renewals can be done by mail.

U.S. travelers can also use a passport card to travel to Canada and Mexico, as well as to the Caribbean and Bermuda. It’s a less expensive alternative to a passport book if you don’t intend to travel outside of these regions.

A NEXUS card is typically used by travelers who frequently cross the border into Canada, but who don’t plan to travel overseas. Note that NEXUS cards can only be used for travel to Canada; travelers to Mexico must have a passport or passport card. Applications are available at the U.S. Customs and Border Protection’s Trusted Traveler Program website. The application process can take as long as eight weeks.

Flying to Canada

U.S. citizens traveling to Canada for fewer than 180 days don’t need a visa. If you’re a permanent resident of the U.S., rather than a citizen, you should travel with proof of permanent residence and a passport, even if you have a NEXUS card. Customs may ask to see these documents. Permanent residents also need an Electronic Travel Authorization; apply for the ETA online with your passport and have a credit card handy to pay the nominal fee.

Some airports in Canada, including those in Montreal, Vancouver and Toronto, have NEXUS kiosks that allow passengers to move through customs more quickly.

Flying to Mexico

As with Canada, visitors staying in Mexico less than 180 days don’t need a visa, but for travel beyond the border zone or staying more than 72 hours, you’ll need a tourist card. You’ll be given one on board your flight and asked to fill it out before getting to customs. The cost of the card is included in your airfare. Keep it with you at all times while in Mexico and report it immediately if you lose it.

Traveling With Minors to Canada and Mexico

If you’re traveling with a minor, you must have proof of citizenship for that child. Single parents should have documentation of custody, such as a divorce decree or death certificate affirming their status as the child’s sole custodial parent. If you share custody with another parent or if the child is not your own, it’s wise to travel with a notarized letter of consent from all parents in case border officials ask for proof that you have authority to take the child cross the border.

Travelers aged 16 and 17 should have their own recognized forms of identification appropriate for travel to Canada or Mexico.