The primary technique used for air traffic surveillance is radar. However, nowadays, its role in surveillance is gradually being replaced by the recently adopted Automatic Dependent Surveillance-Broadcast (ADS-B). ADS-B offers a higher accuracy, lower power consumption, and longer range than radar, thus providing more safety to aircraft. The coverage of terrestrial radar and ADS-B is confined to continental parts of the globe, leaving oceans and poles uncovered by real-time surveillance measures. This study presents an optimized Low-Earth Orbit (LEO)-based ADS-B constellation for global air traffic surveillance over intercontinental trans-oceanic flight routes. The optimization algorithm is based on performance evaluation parameters, i.e., coverage time, satellite availability, and orbit stability (precession and perigee rotation), and communication analysis. The results indicate that the constellation provides ample coverage in the simulated global oceanic regions. The constellation is a feasible and cost-effective solution for global air supervision, which can supplement terrestrial ADS-B and radar systems.