The 87-year-old - who served in the 208th RAF Squadron and in Egypt, Cyprus and Malta - had been joining in the celebrations at the Brighouse 1940s Weekend when the memorabilia was taken.
He was awarded several medals for his service and left devastated by the theft.
Police were called to a Brighouse pub in the early evening of Sunday, June 5 and asked to help
Officers conducted enquiries, with assistance from those at the pub, and within an hour had identified a suspect - a man in his 60s.
He was arrested and, following a house search, officers found the stolen beret.
Later that evening, officers were able to return the hat to the veteran.
Sergeant Joshua Allgood, of Halifax Neighbourhood Policing Team, said: “I am so glad that, with the help of the community, we were able to reunite a hero with his beloved military beret.
“We owe a debt to veterans, and crimes against them will simply not be tolerated."