In an attempt to remain incognito, the pair boarded their 9.55am flight before any other passengers and headed straight to the back of the plane, next to the rear toilets.
They also took up three rows of economy seats on both sides of the aisle, even though there were only themselves and three "edgy and nervous" bodyguards in their party.
Harry, 33, took the seat next to the window dressed in jeans, a jacket and with a baseball cap pulled over his face.
Meghan's brother Tom spoke to DailyMail.com just days before the New Year began.
Before ringing in the New Year on a sour note, Tom spent his Christmas at home in Grants Pass with Blount, 37, and her seven-year-old son.
He has not seen or spoken to his 36-year-old half-sister since 2011 but says he and Meghan are not estranged but lost touch after she moved to Toronto, Canada, to take up a role in Suits.
"She got to the point where she got busier and busier so it was really hard to nail her down," he explained to DailyMail.com.
"It's not really that we grew apart, it was she was out there [in Toronto] doing her job – it was the biggest deal she got on TV so she had no time.
"But we spent a lot of weekends together with our grandmother [Doris Markle] before she left."
He is now hoping that the Markle clan will one day be reunited for Christmas and says that while he doesn't expect an invitation to Meghan and Harry's May wedding, it would mean a lot to get one.
The 51-year-old, who was arrested himself last January for putting a gun to his fiancée's head, was released without charge, added: "I don't know if she gets to invite who she wants. But she'll reach out if she wants me there - she'll call me. She knows where to find me.
"But that's up to her, there's no pressure. I wouldn't mind seeing my little sister have the biggest wedding in the world – that would be incredible.
"Of course [it would mean a lot]. I didn't go to her last one in Jamaica, I was working or something. But if my dad doesn't walk her down the aisle, then I will."
