Rockoons: Rockets lifted by balloons to the stratosphere where they then take off. They save about 50% of their fuel cost and can handle a larger payload because the balloon lifts them for free.

I read about this in an article about Van Allen, who died recently at the age of 91. He discovered the Van Allen belt this way. It is a Steam Punk idea and deserves to be included in a story. I hope I can come up with something, just because The Rockoons is such a good title for a story.