Rain is drizzling as we gather on the runway at the Stuttgart army airfield in southern Germany. It's 2:30 a.m., time for takeoff. A Dash 8 airliner is ready for boarding. The military plane will take us to Sirte in Libya. In 2015, the extremist group known as the "Islamic State"  turned the coastal city into its largest stronghold outside Iraq and Syria . Only after months of heavy fighting was it liberated by Libyan armed forces, with support from US airstrikes . But this was not the last battle in Sirte. The country was already engulfed in a civil war.   An exercise to unify Libyan forces After years of fighting, rival factions agreed to a ceasefire in 2020. But the oil-rich nation has remained  divided between two administrations since 2014. Now Libya's west is controlled by the Government of National Unity (GNU), an internationally recognized UN-brokered provisional government based in Tripoli under Prime Minister Abdul-Hamid Dbeibah.…