“The government convenes the greatest highway bidding in the country’s history.” That announcement in Lima newspapers in March 1964 presented the Tarapoto-Río Nieva road to the public in a fashion typical of development boosterism—brash, bold, and only partially true. Tarapoto, nestled as it was in the remotest corner of the Huancabamba Depression, was only reachable by air on its western approach, and the new highway promised at last to connect coastal markets with the vast arable lands of the Huallaga Valley. The Huallaga, a diverse and dynamic area of the Western Amazon, was the site of rich, transnational imaginings for a host of actors ranging from national planners and global construction giants, to early climate scientists, campesinos and cocaine cartels. The highway was the lynchpin in President Fernando Belaúnde Terry’s pet project, the Carretera Marginal de la Selva, which enlisted Bolivia, Peru, Ecuador and Colombia in a quixotic enterprise aimed at colonizing the eastern Andean flank through one vast road network. Billed as a response to worries of demographic explosion and concentrated land ownership, politicians and international boosters resorted to racial and gender imaginaries to tout La Marginal as a crucial motor of economic growth and regional interdependence that hinged specifically on exploitation of the subtropical dry forests that dotted valleys like the Huallaga. La Marginal represented the reigning development doctrine’s imposition on the Huallaga landscape and a critical component of its construction was a scientific appropriation of the region’s socio-ecological realities. One phenomenon that fed this boom in Huallaga development was the early introduction and utilization of aviation as a means of transport and study.