Several international airlines posted advisories on their Web sites regarding extra screenings and carry-on bags for international U.S.-bound flights, saying that the U.S. government's revisions have prompted changes for passengers flying to the United States.
Although jets are pressurized so that the cabin environment resembles an altitude of around 8, 000 feet, some people report that flying (possibly from the changes in pressure and resulting decrease in oxygen concentration) causes symptoms such as headache, fatigue and nausea.