United Technologies said on Sunday that it planned to combine its aerospace business with Raytheon, uniting the two into a new manufacturing giant in the worlds of aerospace and military weapons and aircraft.

If this all-stock merger goes through, it would be the latest example of consolidation within the military and aerospace industries, creating a new colossus built to thrive in boom times and weather leaner ones.

Together, the aerospace businesses of Raytheon and United Technologies produce Pratt & Whitney engines, Tomahawk missiles and the F-35 fighter jet. The combined company — which will be called Raytheon Technologies — would have about $74 billion in expected sales for 2019.

The combination would become one of the biggest deals of 2019, at a time when the world of mergers has felt some pinch from economic uncertainty and, in the case of some big transactions, greater antitrust scrutiny. As a selling point of their union, both United Technologies and Raytheon played up the fact that neither company has much overlap, hopefully insulating their deal from regulatory blocks.