Meghan and Harry spent three days in the Big Apple to mark Veterans Day and attend events in the city before flying back on November 13.
A picture shared online by a fellow passenger appears to show a suited Prince Harry wearing a face mask leaving the plane after it landed in LA.
It comes after the couple were accused of hypocrisy in September when they flew home from a climate change event on a private jet.
The passenger wrote on social media: ‘Ok this might sound unbelievable and I couldn’t get a good picture and I get [sic] you can say this could literally be anyone….BUT….Prince Harry and Meghan were on our flight to LA last night!
Pictured: The royal couple attended the Veterans Day Salute to Freedom gala Museum in New York so former soldier Prince Harry could present fellow veterans with bravery awards
A photo supplied via Archewell showing the Duke and Duchess at the Intrepid Museum
‘We were held up for about 20 minutes from our departure time and they were snuck into the last 2 seats.
‘We didn’t even know until a girl waiting to get off the plane next to us pointed them out. I couldn’t get my phone out fast enough but it was them.
‘They were quickly whisked away and we were in shock that we were so close and breathing the same air as our beloved royals!’
The Sussexes’ three-day New York excursion included a stay at a luxury apartment on Manhattan’s East Side and two online summits.
The couple attended a red carpet gala on Wednesday honouring veterans at a museum aboard aircraft carrier USS Intrepid moored in Manhattan.
At the red carpet event, former soldier Prince Harry presented Intrepid Valour awards for bravery to five fellow veterans.
The morning after the gala, Prince Harry and Meghan Markle were spotted leaving their NYC apartment on Veterans Day as they headed to a New Jersey army base for a special event
Prince Harry and Meghan Markle are seen on Thursday, November 11, visiting Joint Base McGuire-Dix-Lakehurst in New Jersey to mark Veterans Day during their trip to New York City
Pictured: The couple ate lunch with the service members, with veteran Prince Harry beaming as he shared stories of a decade in the British army which included two tours of Afghanistan
During his speech, Harry spoke about his service, which included two tours of Afghanistan, and said it had helped shaped the person he is today.
On Thursday, Meghan and Harry attended a luncheon at Joint Base McGuire-Dix-Lakehurst in New Jersey.
Earlier this month, the couple pledged that their foundation Archewell would go carbon neutral by 2030.
The couple have been branded hypocrites for their use of private jets as well as their recent decision to publicly and financially back an ‘ethical’ Wall Street fund that invests in oil and gas.
The Duke and Duchess of Sussex, who are currently living in their $14 million mansion in California, shared a mission statement on their Archewell foundation website stating that they will work with an ‘independent consultant to track all Archewell-related activities’ from inception to ‘understand our collective footprint’.
Posting on Archewell earlier this month, Harry and Meghan commented that they have ‘actively made choices to offset and balance their carbon footprint’ but that ‘nearly every activity in daily life results in the release of carbon into the atmosphere’.
Prince Harry and Meghan Markle arrived back in Santa Barbara on a private jet as they gave long hugs to staff including Archewell’s CEO Mandana Dayani (pictured right next to Meghan)
The couple gave a speech at Global Citizen Live, an environmental event to tackle climate change held in Central Park in September, before they took a private jet back to their LA home
They added that they will be looking at ‘what they eat’ and ‘how often they eat it’ as well as their commute and use of heating and electricity in order to cut down their footprint.
The couple were accused of hypocrisy in September after they left a concert urging action on climate change and extreme poverty on a private jet.
The two attended Global Citizen Live, a 24-hour concert, dubbed ‘Wokestock’, that featured performances from Stevie Wonder, Jennifer Lopez, BTS and Elton John, among others.
The event called on the wealthiest nations to meet a £70 billion-a-year promise to help developing countries become green, and for the US to halve its emissions by 2030.
But the couple flew home to their home on a Dassault Falcon 2000 private jet, according to The Sun
Touching down in their private jet, the virtue signalling couple embraced members of staff before heading back to their Montecito mansion.
A flight on a private jet from New York to California is estimated to produce 17 tons of carbon emissions.