A lavatory can be defined as one of three things:
- A room equipped with washing and often toilet facilities; a bathroom.
- A washbowl or basin, especially one permanently installed with running water.
- A flush toilet.
As per regulations set by the United States government, every commercial airliner must have a lavatory on board. This is of great benefit to the passengers because who wants to be trapped on an airplane for a commute and not be able to go to the bathroom? On the ground, all buildings, whether commercial or residential, must have at least one bathroom and a source of running water. However, in general aviation, often the planes are way too small and only carry 1 to 4 people, so a bathroom is not necessary. Not to mention that general aviation flights are typically much shorter and the distance flown is not as great as on airliners, so the need for a lavatory is significantly reduced.
In the charter industry, it is in the best interest of the charter company to equip their aircraft with lavatories. Charter customers spend decent money to fly in a jet that has the best comfort, convenience, and features. Flying in a charter jet compared to flying first class in an airliner is like riding in a BMW compared to a limousine. Both are really comfortable. Both have great features, but the BMW is personal, and the limousine is a group ride. If you rent a charter jet, you should have all the comfort and convenience of a first-class flight on an airliner with the privacy of your own bedroom.