Whenever you're thinking about vacationing somewhere international, the very first thing you should do, before absolutely anything else, is check out your passport, specifically the expiration date. Even if you think you have a while before it expires, even if you just used it, even if it's a pain to find it. Trust us: If your passport expires and you need to travel, you are going to deal with a whole slew of problems that no one wants to deal with.
But we all make mistakes sometimes. It can be easy to get caught up in the vacation-planning moment and book plane tickets before making sure your passport is still usable. It's happened to the best of us: you plan everything out, you're ready to go, and sometime in the near future before your trip, you look at your passport and realize it has expired already.
If this happens a few months before, you're probably OK — you can just get it renewed. Even if this happens a few weeks before, it'll be fine — sure, you're going to have spend more money for a rush renewal, but it'll work out. But, if it happens a few days before? Well, that's a whole other story.
Here's the thing when traveling with a passport: if you are flying international, it absolutely cannot be expired. In fact, it can't even be close to expiring: for travel in nearly every other country, including Canada and Mexico, you won't be able to fly if your passport is expiring in the next six months. So, not only do you need to make sure your passport isn't expired already, but you need to make sure it won't expire within six months of your travel date.
If you do notice your passport is expired or expiring soon, is it worth it to still head to the airport and try to get on an international flight? In a word, no. It's really not. Airport security will almost definitely not let you get on the plane, and you'll just end up wasting a lot of time and money. If, for some strange reason, you're able to board with that passport, don't forget that coming home from a foreign country could be a very different story. Do you really want to get stuck in another country without a passport? Probably not.
If you're flying domestic, however, an expired passport shouldn't be an issue, as long as you have another valid form of United States identification, like a driver's license. You don't need a passport to fly within the U.S., you just need a valid ID. So, if your passport is your only ID, and it's expired, then it isn't valid and won't work. But if you have other photo ID, like your license, you'll be fine.
What are you supposed to do if you're flying international and have just realized your passport is no good? You have two options: attempt to get an expedited passport in time, or cancel and reschedule the trip. If you want to get an expedited passport, it's possible - it will just cost you some time and effort.
As soon as you figure out that your passport is expired, try to make an appointment with the U.S. Passport Office (that's if you have more than 18 hours but less than two weeks before your flight). If you can't do that, get to a passport agency immediately. Get ready to wait on a long line and probably do a bit of begging. You should also come prepared: in some states, you will need proof of travel within 14 days. You'll also need to pay, which can vary, but will likely be around $170. Check out the list of agencies on the official government site, because they aren't in every state.
Expediting your passport should work out, but there are no guarantees that you'll get it in time if you are trying to right before your flight. So, it's always best to play it safe! Keep on top of your passport expiration date, and save yourself the trouble.