The alternative energy technologies, the low energy consumption technologies, the supersonic flight technologies, and the integrated application of the three technologies are the main development directions of the future large airliner. The alternative energy for the large airliner mainly refers to the green and low carbon emission fuels, for example the normal temperature liquid SAF (Sustainable aviation fuels), the cryogenic liquid hydrogen and LNG (Liquid natural gas) fuels. The low energy consumption technologies for large airliner mainly refers to the energy-saving aerodynamic configurations, energy-saving propulsion technologies, and the integrated application of the two technologies, for example the BWB (Blended wing body) airliners and the airliners with large aspect ratio wings, the energy-saving propulsion technologies including extra-large BPR (Bypass ratio) or GTF (Gear transferred fan) turbofan engines, the low noise propfan engines, and the BLI (Boundary layer ingestion) and distributed propulsion methods for integrated configurations and propulsions. The supersonic flight technologies for large airliners mainly refers to the Mach 2–3 supersonic airliners and the future horizontal takeoff and landing hypersonic airliners, the sonic boom depression, the technologies to resolve the conflicts of the low speed states and the high speed states in both the aerodynamic configurations and the propulsion systems are the key design technologies. This article elaborates on the development trends and key technologies of alternative energy sources, low energy design, and supersonic technology for large passenger aircraft, providing new ideas for the future development of civil aviation.