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For the Duke and Duchess of Sussex though, flying commercial means something rather different than it does for us.

They don't typically just enjoy the perks offered to first class customers. Theirs is a world of exclusive lounges, handpicked cabin crews, private airport entrances and chauffeured cars right up to the steps of the aircraft.

So what can the royals expect as they embark on their first royal tour of Africa?

One former member of British Airways cabin crew told CNN that the day they flew Prince Harry several years ago was unlike any other.

"What amazed me was how low key it was," they said.

"Once we arrived at London Heathrow we were on stand within five minutes of landing, and he was off the plane before we turned the lights up.

"He was in first class on a jumbo [747, where there's a door at the front of first class in the nose of the plane] so the airbridge was placed at the door nearest him and he was whipped off before the rest of the passengers took their seatbelts off.

"And he'd been brought on board by special services [British Airways' VIP liaison staff] and arrived in a special car from a separate lounge.

"He sat with his minders in first, while others in his team sat in business class." The rest of the passengers were none the wiser about their famous fellow traveler, they said.

As for the all-important question, the flight attendant -- who asked not to be named -- says Harry was "absolutely delightful."

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They fly among us -- but you'd never know

That level of privacy -- or separation from the great unwashed -- is par for the course in the aviation world.

There's little need to take a private jet with the VIP services offered by both airlines and airports around the world. Celebrities, politicians and royalty can fly commercial without their fellow passengers being aware of their presence.

It tends to happen on long haul flights, says Carolyn Addison, head of product at luxury travel company Black Tomato. Where a private jet within Europe costs around $25,000, flying London to Los Angeles would top $125,000. Few A-listers can stretch to that.

In comparison, a first class ticket on British Airways from London to LA starts at a rather more reasonable £3,121 ($3,900). Tickets to the Duke and Duchess of Sussex's next destination, Cape Town, start from £4,064 ($5,071) return.

Secret lounges

The Private Suite at LAX Courtesy The Private Suite

Forget business class and even first class lounges. Major airports have private suites for their top tier travelers -- and they're usually drive-in. Those who book them get to skip the lines for check in, security and passport control -- all of which is done in the privacy of the suite.

Take Los Angeles International Airport, which, for obvious reasons, has its A-list travel procedure down to a tee.

The Private Suite , which opened in 2017, is an independently owned and operated private terminal, the other side of the runway from the main airport.

Visitors are chauffeured directly to the terminal, have their baggage processed on arrival, and are led to one of 13 individual suites.

Each comes with its own bathroom, entertainment system, and kitchen area with candy dispensers and a fully stocked fridge. Pillows, earplugs and kids' toys are available to take onto the plane, and there's a full a la carte menu service.

From there, you go through a private passport control lane and onto the tarmac, where a BMW 7 series deposits you at the foot of your plane, your hand luggage is carried up in front of you, and you board the plane ahead of other passengers.

London Heathrow is equally swanky. Its Heathrow VIP program sees passengers chauffeured to a private entrance of the airport in a BMW 7 series, and whisked through to the Windsor Suites.

Their baggage is checked and they're given a private suite, complete with a menu developed by Michelin-starred chef Jason Atherton. A butler and personal shoppers are on hand, and there are also tax refunds for thrifty VIPs.

When it's time to board, they head through a private security lane and get the BMW to the aircraft steps. They can be on the plane without any paparazzi or cameraphone-wielding passengers being any the wiser.

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VIP handlers

AA's Five Star Service program sees clients whisked to the plane in Cadillacs American Airlines

In fact, at LA, celebrities only need to be papped if they want to, says Janelle Anderson, American Airlines' VP of global marketing.

"You see the up and coming ones [going] through LA security, but it's a choice," she says. "Entertainment industry people use our service to travel without a lot of commotion."

AA's Premium Services team coordinate A-listers, politicians and royalty through The Private Suite at LAX, using what it calls its Five Star Service program.

Clients and their management can email, call or text their handlers. "You'd be surprised at how close they can get," says Anderson. "They get to know some of the celebrities pretty well."

For real high rollers, in traffic-congested New York and Los Angeles it offers helicopter transfers, allowing customers to get from the city to the lounge or gate in under seven minutes.

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AA also offers a scaled-down version of the program. If they're happy to share the lounge with mere mortals, VIPs can elect to check in at the dedicated first class area -- which at London Heathrow is in a separate building from the main AA terminal -- and get escorted through security (where they skip the line) to the Flagship Lounge, where there's a sit-down meal service of locally sourced food.

From there, they're escorted to the gate, where they can either pre-board or go on last, depending on their preference.

"Some go on first and put on a hat and sleeping mask, and some do the opposite," says Anderson. Either way, "people using the service are generally trying not to be seen."

It's not just celebrities who use these services, according to someone who books them.

"You'd be surprised," says Grant Holmes, who organizes trips for his VIP clientele as MD of A Small World Travel, part of the Virtuoso travel adviser network. "It can be someone wealthy who just doesn't like airports or crowds, may be mobility impaired, and has the money -- so why not do that?

"It can be people who are very well known in the business world who don't want people pitching to them as they walk to the gate.

"It's about privacy and ease more than anything. We get you in and out hopefully without anyone seeing you."

Most of his clients choose to board last and get off first.

If a celebrity is particularly keen on privacy they can book under a pseudonym, he says. Then, at check-in, the booking can be switched to their real name. But that's very unusual.

On board

British Airways First Class Courtesy British Airways

Celebrities love the front row of first class for the privacy it offers -- unless there are bathrooms at the front, there's likely to be no one walking past except for cabin crew.

But if a civilian has already booked that seat, there might be a tussle.

Our former British Airways flight attendant reckons a normal passenger would always be moved to accommodate a politician or royalty. An aviation insider who knows how the royals travel agrees.

And Grant Holmes says that sometimes first class passengers might have their seats switched for landing, so a high profile traveler can be closest to the door, to hop off first.

But Janelle Anderson says that would never happen on American Airlines. "Of course we love our celebs but we really do believe all our customers are equally important," she says. "If you've already picked it, you'd keep it."

Customers in first and business class are pretty discreet anyway, says Black Tomato's Carolyn Addison.

"People tend to be very respectful, and the staff are there to check their flight isn't being interrupted by gawking fellow passengers," she says. "Plenty of high profile people fly [commercial]. Technically they could buy extra seats to have a buffer around them, but I've never heard of anyone doing that."

Crew are informed about their high-flying passengers during their pre-flight briefing. They might get additional messages about the celebrity in question -- for example, if they want to be addressed a certain way (many fly under their real names, which are different from their stage names).

And if they're high security passengers, the flight manager might tell crew that they're not allowed in first class unless they're working the cabin.

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Crew are not allowed to ask for selfies or autographs unless the VIP offers -- but many do. "The Brad Pitts of the world will come into the galley and have a coffee with you," says one flight attendant. "It's the ones trying to prove they're somebody who can be s---s."

One aviation insider says that sometimes celebrities book the VIP service in order to be noticed.

"You can have someone like Jonny Lee Miller who travels like anyone else, gets on the plane and is unfailingly polite," they say. "Or you have others who'll book special services because they want people to look.

"The question is, are you important or self-important? And if you're important, is there a security issue around mixing with the public?"

Royal extras

The atrium to the private suites for the Heathrow VIP program Heathrow Airport/Richard Boll

The aviation insider -- who spoke on condition of anonymity -- tells CNN that the treatment the British royal family get depends on "where they fit in the hierarchy."

The Queen, for example, doesn't have a passport, so there's no passport control for her. When traveling through Heathrow, she'll use a specially dedicated royal lounge.

Senior royals -- the Duke of Edinburgh, the Queen's children and their spouses -- also get to use the royal lounge, although they do have to go through immigration and security there.

As the next generation, William, Kate, Harry and Meghan don't qualify for the lounge, and would normally have to use the Windsor Suites alongside other Heathrow VIPs, says the insider.

If they're traveling on official business, however, they can be "upgraded" -- so Harry and Meghan will presumably kick off their Africa visit with a trip to the royal lounge.

They'll likely get special treatment on board, too. The British Airways staffer who worked a flight with Prince Harry (and has also carried Prince Andrew) says that standards are always upped when the royal family flies on the national carrier.

"They will get perfect aircraft, and cabin crew will have the "i"s dotted and the "t"s crossed when it comes to their uniform. Hats are a must.

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"If it's the Queen, sometimes a special crew who have previously worked with the royal family will be rostered to work.

"Other members of the royal family wouldn't normally get preferential treatment, but because Meghan and Harry are so high profile at the moment, I think they might."

One other thing to know about the royals, is that although cabin crew are allowed to speak to them, they're not allowed to request any money.

So if Harry and Meghan want to buy any duty free, it'll be up to one of their staff to pony up.

They're unlikely to have the cabin to themselves, though, according to the aviation insider. "If you take the Cambridges going on vacation to Mustique, they tend to book a few seats in row 1 and 2 for themselves plus their private secretary and one security guard, but the rest of first could be sold to other travelers."

The same goes for the Sussexes' flight to Cape Town. But don't get too excited.

"Yes, you might be in the same the same cabin as Harry and Meghan, but you won't be sat next to them and you won't be holding the baby."

The bottom line

There's no need to be a celebrity to live this lifestyle -- anyone can pay for these services, as long as they're traveling first or business class. The Heathrow VIP experience costs £3,300 (£2,750 plus tax) for three people. "If you split that between three of you, it becomes £1,000 each," says Carolyn Addison. "It's not nothing but it's not unachievable for a special trip."

The Private Suite at LAX costs $7,500 for four people ($4,500 annual membership plus $3,000 per visit).

Those prices only cover an arrival or departure, however. If you want the service at both ends, you'll have to pay both lounges.

American Airlines' Five Star Service is more affordable. A simple escort service through the airport, including pre-boarding and access to the dedicated Flagship First check in, costs $350 for the first traveler and $100 per additional adult.

The helicopter transfer costs $195 per person for a scheduled flight, or $1,200 to charter the helicopter.

AA also offers a more affordable experience at LAX, where clients arrive, check in and pass security at The Private Suite, but then take a Cadillac to the AA lounge in the terminal, and from there an escort to the gate. This costs $1,200 for two people.