RTX is a large aerospace and defense company with three segments: Collins Aerospace, Pratt & Whitney, and Raytheon. Collins (~34% of sales) supplies aircraft systems and components — landing gear, avionics, nacelles, power systems, and cabin interiors — to Boeing, Airbus, and the military, alongside a large aftermarket business in spare parts and MRO. Pratt & Whitney (~37% of sales) designs and services jet engines, with its GTF (Geared Turbofan) engine powering the Airbus A320neo family and the F135 exclusively powering the F-35 fighter. Raytheon (~32% of sales) is a defense contractor focused on missiles and air defense systems, including Patriot, AMRAAM, Tomahawk, and SM-3/SM-6 interceptors. RTX's business model runs on two revenue streams: original equipment (OE) and aftermarket. OE products — especially jet engines — are often sold at thin or negative margins to win platform positions, with the real profit coming from decades of aftermarket parts, MRO, and upgrades once the product is in service. Aftermarket is RTX's most profitable channel, scaling with flight hours and the size of the installed base. Defense revenue flows primarily through U.S. government contracts and foreign military sales. A key near-term issue is Pratt's "powder metal matter," a quality defect in certain GTF engine components requiring accelerated inspections and fleet repairs, with RTX expecting ~$3B in cumulative customer compensation payments. RTX's growth is driven by rising commercial aircraft production rates, growing global air travel, and surging defense demand for munitions and missile defense systems.