You don't need much room; Gulf Aviation (later Gulf Air) had a successful birth in the galley of a BAC 1-11. The sector was Dubai - Abu Dhabi, so the process was actually completed on the ground, with passengers filing past, some averting their eyes, others not.
Next morning's Gulf News carried the Press Release hastily sent to them, but they changed the headline to "GULF AVIATION - AN EARLY ARRIVAL AT LAST".