Both pro-GNA and pro-LNA air forces suffer serious lack of qualified air force personnel, especially the pro-GNA Libyan air force – most of their pilots are over 50 years old, well above air-force retirement age, and very few have high-quality flight skills. Because of that, and due to many of its Libyan-born pilots and air force personnel being killed in the war, both sides, especially pro-GNA air forces, are relying more and more on foreign mercenaries to both fly and repair their fighter jets, with mixed results. Many of these foreign mercenaries fighting for pro-GNA forces are from countries such as Portugal, Ecuador, US, Turkey and Ukraine, while fighter jets from pro-LNA forces are reportedly being flown by mercenaries from UAE, Egypt and Russia.