The Northrop F-20 Tigershark was a privately developed fighter aircraft meant to be sold to foreign militaries as an alternative to the F-16. It shared some design similarities to Northrop's F-5 but had better performance due to an upgraded engine. Three prototypes were built in the 1980s but no sales materialized as potential customers preferred the F-16. The project was ultimately cancelled after six years due to high costs and lack of orders.