Hello and thanks for the query, It is generally not advised to travel in the third trimester that is after 28 weeks. Also you have a low lying placenta. This may not be an issue if the ultrasound is an old one as the placenta tends to go in the upper segment as the lower part of the uterus outgrows the upper. So please check if the ultrasound was a recent one. If not get a recent scan done to check placental location. The problem with a low placenta is potential bleeding, and if it occurs during flight there would be no treatment available. If travel is unavoidable, use tablets that relax the uterus like isoxsuprine and progesterone during travel to help avoid preterm labor. They can be used with prescription from your doctor. Also avoid prolonged standing and if in flight, take short walk during flight to help blood circulation. You may also need a certificate of fitness to travel from your health care provider as this is a rule in some airlines for pregnant women so have this checked. Please discuss these issues with your doctor and understand the risk of bleeding before choosing to travel. Hope this was helpful. Have a safe pregnancy and delivery. Dr Madhuri Bagde Consultant Ob Gy