Open-source airline route maps from 1999 and 2018 created using Python and BTS data (see corresponding comment for clarifications + GitHub link) [OC] : r/dataisbeautiful
International Flights Route Map, Schedules and Airline Contacts | OR Tambo Airport
World Flight Map, World Air Routes Map
Show Off Your Infinite Flight Route Map - #14 by candrej - Live - Infinite Flight Community
Visualizing Airline Routes and Hubs – Saumik Narayanan
Archivo:World-airline-routemap-2009.png - Wikipedia, la enciclopedia libre