A Ukrainian Air Force F-16 fighter jet flies in an undisclosed location in Ukraine, which only received a limited number of jets for a small cadre of trained pilots, making a recent loss significant.AP Photo/Efrem LukatskyUkraine lost one of its few F-16s last week while it was defending against Russian missiles and drones.It was initially thought that Kyiv would use its F-16s for air defense, given the heightened risk of other missions.But the big Russian attack and the jet loss last week show even defensive missions are still dangerous.Before Ukraine received its first batch of F-16s a few weeks ago, one of the big questions surrounding the transfer was how Kyiv would make use of its small inventory of NATO-provided fighter jets.When the jets arrived in Ukraine, initial imagery of the F-16s and their missile loadouts suggested Kyiv would use the fighter aircraft in an air-to-air role as opposed to offensive missions where they'd be more vulnerable.Last week Ukraine's F-16s flew in combat, defending against a massive Russian aerial attack.