Airman Corrie Mckeague was first reported missing when he failed to turn up for parade at RAF Honington on Monday, 26 September.
It was thought he may have attempted to walk back to the airbase 10 miles away after a night out in Bury St Edmunds.
A couple of days later, CCTV footage was released showing the gunner in the Brentgovel Street area of the town in the early hours of Saturday, 24 September.
A search was subsequently carried out on the road between the base and Bury St Edmunds.
But there was no trace of him leaving an area in Brentgovel Street known as the "horseshoe".
Andy King, chairman of Suffolk Lowland Search and Rescue, who'd been enlisted to help the police, said: "We always start looking in the place they were last seen, and in Corrie's case, that was the 'horseshoe'."
Mr King continued: "We did a very detailed search of a 200 metre [656ft] radius around the area, but it turned up absolutely nothing.
"That's not unusual, though, so then we continued to plan our search and come up with possibilities of what might have happened to him."