Complex sentence: Similar V/STOL operational aircraft include the contemporary Soviet Yakovlev Yak-38 as well as one variant of the Lockheed Martin F-35 Lightning II, which is currently under development.
Split into simpler sentences: Similar V/STOL operational aircraft include the contemporary Soviet Yakovlev Yak-38. A V/STOL variant of the Lockheed Martin F-35 Lightning II is currently under development.