Michal Konrad Herba, 36, appeared in court for an extradition hearing following his arrest in Tividale, West Midlands, on Wednesday.
He is the brother of Lukasz Pawel Herba who is being held by Italian police over the alleged kidnap in Milan.
Michal Herba denies involvement. The case was adjourned until 25 September.
Prosecutor Florence Iveson told the court that he was suspected of kidnapping and unlawfully detaining Ms Ayling in a "joint enterprise" with his brother and other "unidentified persons".
The 20-year-old model was allegedly drugged and a ransom of â‚¬300,000 (Â£270,000) was demanded, the court heard.
Defence lawyer Katherine Newbey said "no evidence had been served in the case" and her client "denies involvement".
Mr Herba did not consent to extradition, meaning that a full hearing will have to take place.
Deputy Senior District Judge Tan Ikram remanded the suspect in custody, saying he was satisfied there were "substantial grounds" to believe he would fail to surrender if he was released.
Mr Herba is due to appear in the same court by video link for a bail application on 23 August.
A full extradition hearing has been scheduled for 25 September.
Ms Ayling, from Coulsdon, south London, arrived in Milan on 10 July for a photo shoot.
Italian police say she was attacked by two men, drugged with ketamine and abducted, apparently to be sold in an online auction.
She is believed to have been transported in a bag to an isolated village near Turin, Italy, but was released on 17 July.
Ms Ayling's lawyer Francesco Pesce has said she was told she would be sold in the Middle East "for sex".
Speaking after the alleged abduction, Ms Ayling said she feared for her life throughout the "terrifying experience".
"I'm incredibly grateful to the Italian and UK authorities for all they have done to secure my safe release," she said.
Italian police documents claim that suspect Lukasz Herba said he had got involved in order to raise money for cancer treatment.
The Polish national, who lives in Oldbury in the West Midlands, told investigators he drove her to the British consulate in Milan and released her before the sale went ahead.
The brother of the alleged captor of British model Chloe Ayling is to fight extradition to Italy, Westminster Magistrates' Court has heard.