Re: Before SpaceX it would have been diapers all the time
There are toilets on small private jets, which amount to one of the rear seats with a curtain round. Remove the cushion and the bog is waiting. Nobody ever wants to use these, so experienced travellers make sure they are prepared for the journey, and do not partake the onboard refreshment until they are sure they are home "dry". Inexperienced travellers soon learn to do the same. People who are unwell should not step aboard.