Originally Posted by
jzoz01
Definitely not dumped in flight (or while on the ground). Just like a boat, train, or RV, commercial airplanes have some sort of septic tank and use vacuum toilets.
Also, many smaller boats (not the cruise lines) also dump directly into the sea. Most of the live-aboard diving boats that I've been on dump directly into the ocean, thus the warning not to use the head while diving/snorkling groups are in the water (if possible)......