On Main Street near the Longley Bridge Thursday afternoon, a group of firefighters from Auburn stood on one side of the road, their counterparts from Lewiston on other. Between them, high above the street, a 50-foot flag fluttered in the wind. It had been hoisted there by the fire crews who draped the flags from ladders assembled like a steeple 30 feet over the pavement. The purpose: to greet a throng of walkers heading into Lewiston over Longley Bridge as part of the annual Make-a-Wish Foundation’s walk-a-thon. Hundreds of people gathered in downtown Auburn before making the trip across the bridge into Lewiston, where they walked beneath the flag and turned right onto Canal Street. For more than an hour, drivers heading to or from Auburn honked their horns or hollered from car windows in support of the walking group and the display of the flag.