English: A schematic of HOTOL. HOTOL (or similar jet-propelled aircraft) could be possibly build to delivering packages and personnel over long dictances at a cheap cost. A emissionless external combustion engines such as the one shown at http://commons.wikimedia.org/wiki/File:Hydrogen_Oxigen_External_Combustion_Engine.JPG can be used with HOTOL. The cheap transport is possible trough automation, hereby making use of cheap electronics such as done in Bruce Simpson's DIY cruise missile project. This aircraft could thus be useful for development and environmental projects that require the transportation of great amounts of material (eg waste plastics, ...) or require cheap personnel transports. The schematic was based on an image in the book "Lucht en ruimtevaart" by Hugh Johnstone.