The incident took place on July 31 on a flight from London City Airport. Before boarding the plane, Ryan, 39, had drunk a bottle of port, Ealing Magistrates’ Court heard.
On top of the charge for racially aggravated assault, Ryan was found guilty of being drunk on an aircraft, assaulting a police officer and behaving in an abusive way towards a cabin crew member.
Ryan denied the charges, telling the court his actions were “playful”.
Giving evidence to the court, a different flight attendant said that shortly after the plane departed, Ryan approached her, demanding to be upgraded from economy to business. This was not possible, the flight attendant said, as the plane was full.
“He told me he had a problem, that he was being harassed by other passengers, that he was famous and asked did I know who he was,” she continued.
“He was angry, saying he was a gold-card holder and that he needed to be moved because of this.”
Ryan was said to be “slurring his words and staggering around”.
Blue first formed in 2000, with Ryan joining Simon Webbe, Duncan James and Antony Costa to form the band. They went their separate ways in 2004, before reuniting to represent the UK at the 2011 Eurovision Song Contest.
Last year, Blue returned again to release their sixth album, Heart & Soul, their first release since 2015.