Stephen Mell in his private jet.

A millionaire dad-of-three is facing jail after having sex with a schoolgirl, 15, as he flew a private plane on autopilot mode.

Stephen Mell, from New Jersey, US, groomed the girl after her mum asked him to give her flying lessons, The Independent reports.

Prosecutors heard how the doting dad, 53, whisked her to his £3m mansion where he performed “an oral sex act” on her on 20 June 2017.

He allegedly told her in a text: “If you are nervous it will hurt more. When you are turned on is when it will feel ok.”

On 20 July 2017, he flew with the victim in his private plane from Somerset Airport to Barnstable, Massachusetts “for the purpose of engaging in illicit conduct, specifically, a sexual act with a person under the age of eighteen”, court papers state.

On the flight back, he reportedly put the plane on autopilot to engage in sex acts.

During an August 2017 trip to New York City, Mell again had sex with the girl and took pictures of her naked. He later pressured her to “get the IUD”, referring a form of birth control inserted into a woman’s uterus.

Mell faces sentencing in July on a state charge related to sexual activity with the teen, which he pleaded guilty to earlier this month after admitting endangering the welfare of a child by engaging in sexual relations with a female victim under the age of 16.

He will be sentenced for that charge on 12 July.