Two Ukrainian pilots are currently in the United States undergoing an assessment to determine how long it could take to train them to fly attack aircraft, including F-16 fighter jets, according to two congressional officials and a senior U. ”The defense official added that there are no immediate plans to increase the number of pilots beyond the two currently in Tucson but said “we’re not closing the door on future opportunities. The Russian Air Force has roughly 500 aircraft, the official said, which dwarfs the Ukrainian force