During a healthy pregnancy, occasional air travel is almost always safe. Most airlines allow you to fly domestically until about 36 weeks of pregnancy. Your ob-gyn can provide proof of your due date if you need it. If you are planning an international flight, the cut-off for traveling may be earlier.

In terms of medical and airline restrictions, the "no-fly" period typically begins in the final month of pregnancy. Most commercial airlines permit healthy pregnant women to fly up until the end of their 36th week (approx. 8 months) for single pregnancies, and the 32nd week for multiples. After 37 weeks, the risk of going into labor mid-flight is considered too high, and most carriers will deny boarding. Additionally, for scuba divers, there is a mandatory "no-fly" window of 12 to 24 hours after the last dive to prevent decompression sickness. From an age perspective, some airlines restrict infants under 7 to 14 days old from flying without a medical release. Thus, while there is no "set number of months" for everyone, the final month of pregnancy is the most common time people are restricted from air travel.