The number that frames RTX's 2021 is the split, not the total. The company's 2021 Form 10-K reports total backlog of approximately $156 billion, with the filing noting that included in total backlog is defense backlog of roughly $63 billion. That makes defense about 40% of the runway, and the commercial-aerospace recovery the remainder.
For an analyst, the proportion is the signal. RTX is the rare prime that straddles two demand cycles: government appropriations (Raytheon defense) and airline capex and flight-hour recovery (Pratt & Whitney, Collins). A $63 billion defense backlog inside a $156 billion total tells you how much of the forward book is counter-cyclical and appropriations-funded versus how much rides the commercial-aviation rebound.
The disciplined caveat: backlog is forward revenue, not guaranteed revenue, and the defense portion in particular depends on continued appropriations and program timing. The commercial portion depends on airlines taking delivery and flying. Both are real; neither is booked. Book-to-bill direction across the two halves is what actually moves the thesis.
Entering 2022, the question is whether the commercial recovery keeps lifting total backlog while defense holds its roughly $63 billion base. Track the defense share over the next filings as the mix shifts. Filing on sec.gov; index via EdgarBeast.