if you are going on a long flight it can be normal to take in a washbag (usually with soap and toothbrush in) But just put in a clean diaper and if there is no bin on the plane put the old one back in there Anyway how many people will you know on that plane apart from your family? So dont worry about your diaper being seen. If its a short journey you may want to try drynites (USA Goodnites) They are really good! Anyway good luck