Biden green-lit F-16s in May after increasing pressure from Ukraine and NATO officials, but the timeline for Ukrainian forces to get the prized jets is still up in the air.US Air Force photo by Tech. Sgt. John Raven Ukrainian pilots have been taking English classes between missions. Ukraine's aviation chief told The Washington Post that pilots have had to learn jet terminology. The pilots are training to use US-made F-16 jets in their war against Russia. Ukrainian pilots have been taking English classes in between missions for the past year to prep to fly US-made F-16 fighter jets, the aviation chief of Ukraine's air force told The Washington Post.Brig.