Astronauts are required to wear adult diapers during space walks, take-offs, and landings. Floating urine in a spacesuit poses a safety hazard (drowning).

Pilots on long missions eat light prior to a mission and take candy bars to raise blood sugar levels during the trip. In the event a call of nature arises over the Atlantic.... they go in their pants. They also may wear a diapers but in the military it is not very "macho". You are going to sit in it the rest of the flight anyway. Urine is caught in a catheter.

Thomas Crapper invented the first Flush toilet.

Engineers calculate the maximum water flow in hotels and the system WILL handle it.