Ukrainian F-16s in the air in an undisclosed location in August.REUTERS/Valentyn OgirenkoUkraine isn't flying the most dangerous missions with its F-16s, a top US general said this week.Kyiv flew its new aircraft in combat for the first time at the end of August.But the air-defense mission turned deadly when one of the F-16s crashed — underscoring the risk.A top US Air Force general said that Ukraine is not using its F-16s for the most dangerous missions because the pilots flying them are still new to the fighter jet.Ukraine's F-16s flew in combat for the first time at the end of August when they helped repel a large Russian missile and drone attack.