I've flown many times over the years, most recently internationally to Japan. I have found that the level of security varies from country to country, being most thorough here in the US. Although, even here it will vary from airport to airport. On my most recent trip I found that at TSA the appliance can be picked up even without a pat down. Once spotted, the agent will ask and do a pat down and test your hands for powder residue. No, the appliance does not inflate during flight, your friend will have no woriies in this area. I always empty before boarding and try not to eat anything for a few hours before flying. One thing I do, especially on long flights, is to try to get an aisle seat so that I don't have to climb over people repeatedly in the event that my ostomy is a bit too active.