What is the maximum altitude a manned plane that flies subsonically can reach? Subsonic airplanes can't go as high as super- and hypersonic ones of course, so record holders are the latter ones. But ironically, the altitude record for leveled flight is set by the subsonic NASA Helios propeller aircraft at ~97,000 ft. However that's an uncrewed and weird-looking one. Can manned airplanes that fly subsonically go above the Armstrong line (60-63,000 ft) and higher (either in leveled or in parabolic flight), considering realistic fuel limitations? How high can subsonic airplanes go compared to supersonic ones?