If you're traveling internationally, the short answer is no, you cannot use an expired passport. You must renew your passport if it's expired or will expire within the next six months.

If your passport expires before your flight, you will almost certainly be denied boarding at the airport. Most countries require at least six months of validity beyond your planned departure date to grant entry. In 2026, many airlines use automated systems that flag your document during online check-in if it doesn't meet the "six-month rule" or the "three-month rule" (common in the Schengen Area). If you discover this too late, your only option is to seek an emergency or "expedited" renewal. In the US, you can schedule an appointment at a regional passport agency for "Life-or-Death Emergency" or "Urgent Travel" service (within 14 days), but these slots are limited. Many other countries offer "Tatkal" or "Premium" 24-hour turnaround services for a significant fee. Without a valid passport, you may be able to travel domestically with a Real ID, but for international trips, there is no workaround, and you will likely lose the cost of your flight unless you have high-tier travel insurance that covers documentation issues.