Reason the foreign land-based F-18s are carrier fighters has something to do with the production agreement between Northrop and McDonnell-Douglas. When Northrop wasn't chosen in the Lightweight Fighter Competition (YF-16 vs. YF-17), they passed the plans to McD for them to modify the aircraft to a carrier based version of the F-17, renamed the F-18 (the Navy wouldn't buy carrier fighters from Northrop). Under the agreement between Northrop and McD, McD would be the prime contractor for carrier versions of the F-18, and Northrop would be the prime for the land-based versions. In a stroke of marketing genius, McD sold carrier versions to countries without carriers. Probably an easy sell because other countries wanted versions of the jet operationally flown by the U.S., and the Air Force, Navy, or Marines weren't buying Northrop versions. Northrop got frozen out of producing the fighter they developed, other than manufacturing major sub-components.