[header] How to survive a long flight when you have your period [title] Consider booking an aisle seat. [step] If it is possible, book a seat that is on the aisle. You will likely want to get up every hour or two to visit the restroom, and if you are sitting in the aisle, you won't have to bother any other passengers in order to do so. 
[substeps] If you aren't able to get an aisle seat, try not to worry. Yes, you will have to ask your neighbor every time you want to get up, and yes, they might get mildly annoyed.