How Safe Is a Roller Coaster in the Sky? (SPACE.com) SPACE.com - Last week's nbsp;announcement nbsp;by the Zero \Gravity Corporation that it would be offering weightless flights to paying \customers was good news for thrill seekers. nbsp; Those who sign up for the \experience will be treated to several stomach-rolling climbs and drops. nbsp; \Although the planes used are slightly modified commercial planes, tests have \shown that they can manage the demanding maneuvers.