STRUM, Wis. — The pilot of an ultra-light aircraft was injured seriously when he lost power after take-off and crashed into trees. He was airlifted 20 miles to the Eau Claire hospital. The pilot was attempting an emergency landing, witnesses said. The crash was about 11:30 a.m. at the privately owned Viking Flying Club’s airfield, which has a 2,100-foot unpaved turf runway. There are 30-foot trees 350 feet from the runway. Trempealeau County Sheriff Brett Semingson declined without explanation to release the victim’s name.