Corrie Mckeague, from Fife, vanished after a night out in Bury St Edmunds, Suffolk, on 24 September.
The 23-year-old's Nokia was tracked from Bury to Barton Mills, but was not found.
Suffolk Police said it would be impossible to link the phone back found in Mildenhall, near Barton Mills, with the airman's disappearance.
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The police said the telephone had no essential components. As a result, no further investigations will be carried out on it.
On Monday, it was revealed Mr Mckeague was due to become a father.
Forbes McKenzie, of McKenzie Intelligence Services which was brought in to assist the search, said the whereabouts of Mr Mckeague's telephone was "key".
Mr McKenzie said: "Where the phone finished is indicative of where Corrie last was.
"I'm very interested in what other phones were co-located with Corrie's phone."
Mr Mckeague's Nokia Lumia 435 phone is thought to have been in a black PVC case which was frayed and worn around the edges.
The back of a phone has been found close to where the last signal from a missing airman's mobile was detected.