ABOARD THE USS GEORGE H.W. BUSH (AP) — The crowded skies over Islamic State-held territory have complicated U.S.-led airstrikes targeting the extremists, though military planners are working to keep fliers safe, an American pilot involved in the bombing campaign has told The Associated Press. Lt. Cmdr. William Vuillet also described the efforts American forces use to try to minimize civilian casualties from strikes on major cities like Mosul, where allied forces are trying to sweep the remaining militants out of the western half of Iraq's second-largest city. Vuillet said he believes coalition forces will "eradicate" the extremist group responsible for mass killings, beheadings and other atrocities targeting civilians across the Middle East and around the world. Russian and Syrian aircraft regularly strike insurgents battling to overthrow President Bashar Assad, and Israel carries out occasional strikes aimed at preventing advanced weaponry from falling into the hands of the Lebanese Hezbollah group. Airwars, a London-based group that tracks civilian deaths from airstrikes targeting IS in Iraq and Syria, estimates the over 19,000 strikes conducted by the coalition have killed more than 2,700 civilians.