NATO Is Now Using the F-35 To Make Old Fighters Even Deadlier Italy, Norway, Poland, The Netherlands, the U.S., and the U.K. are all increasing joint 4th-Gen aircraft-F-35 interoperability exercises with one another, as the Pentagon looks to strengthen NATO ties and increase its Russia-oriented deterrence posture throughout the European continent. Italy, Norway, Poland, The Netherlands, the U.S., and the U.K. are all increasing joint 4th-Gen aircraft-F-35 interoperability exercises with one another, as the Pentagon looks to strengthen NATO ties and increase its Russia-oriented deterrence posture throughout the European continent. The numerous activities seek to not only leverage F-35 multinational networking and joint operational capacity but also extend beyond the 5th-Gen fighter to include 4th-Gen aircraft and many non-F-35 countries of great significance to the U.S. and NATO.