The present disclosure is directed to systems and methods for reducing and/or harvesting drag energy from transport vehicles. A system in accordance with a particular embodiment includes a mobile transport platform, a donor substance source carried by the platform, and a thermochemical reactor carried by the platform and coupled to the donor substance. The reactor is configured to carry out a non-combustion dissociation process that dissociates the donor substance into a first constituent and a second constituent. An energy extraction system carried by the transport platform and positioned to extract energy from an airstream passing the transport platform is coupled to the reactor to provide energy for the dissociation process.