This Is What Actually Happens When You Flush an Airplane Toilet

"A vacuum mechanism sucks the waste and blue cleaning fluid into a waste holding tank through a series of pipes. A 'honey truck' collects and disposes of waste after the aircraft lands. That's it-no water is used (as that would add too much weight to a plane), just air and good old-fashioned engineering."

"The vacuum is also pretty handy as it minimizes odors since the waste is trapped in the hold. And yes, airplane toilets do have a distinctive flush noise, which is caused by the vacuum and a built-in high-speed turbine that is used to prevent any solids from clogging the pipes."

"There isn't any danger of flushing the toilet while a passenger is sitting on it because it is tested that way. There is a myth that claims sitting on the toilet can be dangerous, but there is no truth to that."

Airplane toilets operate through a vacuum mechanism that sucks waste and blue cleaning fluid into holding tanks via pipes, with no water used to minimize aircraft weight. A high-speed turbine prevents pipe clogs while the vacuum system minimizes odors by trapping waste. After landing, specialized 'honey trucks' collect and dispose of the waste. The distinctive flush noise results from the vacuum and turbine system. Contrary to common myths, airplane toilets are completely safe to use while seated, as they are rigorously tested. The primary risk is occasional clogging or defects causing minor inconveniences.

Read at Travel + Leisure