Do you know the title of this science fiction move?

A USAF pilot, in a single seat jet, finds nothing on his radio & after landing his air base & the countryside is deserted. He’s unintentionally gone forward in time. Soon he’s in a populated self-contained city. There’s also 1 woman & 2 men from the past who the city government keeps under surveillance with monitoring devices. The woman & men are pilots & scientists who now do technical work for the city. While doing experiments they create steam & noise to mask their conversations. Within the city are a large group of prisoners confined in one area. The pilot falls in love w/the pretty daughter of the city leader. The prisoners escape & the cute young girl dies during an uprising. As the city falls, the pilot carries her body to her father & then uses his jet to return to the present. At the end the pilot tells his story as a warning to stop testing atomic bombs. He has a ring the girl gave him & is suffering from bad radiation burns. Does anyone remember this film & the title?