A canopy door from a two-engine plane belonging to Embry-Riddle Aeronautical University came undone during a training run over Palm Coast’s C-Section around 4:30 p.m. Thursday and fell to earth, slamming the pavement within yards of several houses around a cul-de-sac. No one was injured on the ground, and the pilot and trainee aboard the plane made it safely back to the Flagler County Airport.