Mr Thomas, who sometimes can get confused, was reported missing at 3pm. Police enquiries are ongoing to return him home safely.
He is described as white, 6ft tall, slim build with balding grey hair. He was wearing a fawn jumper and a light-blue jacket.
Anyone who may have seen Mr Thomas or an elderly man matching his description is urged to call North Yorkshire Police on 101 without delay, select option, 1, and speak to the Force Control Room. Please quote reference NYP-27022019-0256.