The announcement means that balloon project Loon and drone project Wing will be independent companies within Alphabet - and in theory could be spun off entirely in the future by the California technology giant.
Wing and Loon have been part of the Alphabet "moonshot factory" known as X, creating projects with potential to disrupt new sectors.
"X's job is to create radical new technologies and build a bridge from an idea to a proven concept," said moonshots "captain" Astro Teller in a blog post.
"Now that the foundational technology for these projects is built, Loon and Wing are ready to take their products into the world"
Alphabet has previously "graduated" its Waymo self-driving car division, along with the cybersecurity unit Chronicle and the life sciences project Verily.
Another moonshot project, the geothermal energy unit called Dandelion, has been spun off as a fully independent company.
Wing is building an autonomous delivery drone service which aims to reduce fossil fuel use and urban congestion, and facilitate disaster relief transport. James Ryan Burgess was named chief executive.
Loon is building a network of balloons, travelling along the edge of space, to expand Internet connectivity to underserved areas and disaster zones. Its CEO will be Alastair Westgarth.
While Alphabet has kept some of its projects under wraps, Teller said the latest moves will allow the company to concentrate on "new moonshot adventures," and ongoing projects including Google Glass, robotics and wireless optical communications.