Pull up your bar stool for cocktails at 35,000ft

Virgin Atlantic's flying barman shows Kate Simon how to mix (and drink) a marmalade martini at 35,000 feet

Taste the difference. In my right hand I have a glass containing a few ice cubes, a big slug of gin, a slosh of tonic and a slice of lemon. In my left is a glass full of ice, with a more restrained measure of spirit, lime has been squeezed in the glass and rubbed around the rim, and the drink has been topped with tonic and served with a sprig of rosemary. Which do you think tastes better?

I'm perched on a bar stool at 35,000 feet in the air, in the Upper Class cabin of a Virgin Atlantic flight to Los Angeles, watching Marc Plumridge, a brand ambassador for Bacardi, performing his role as the airline's "flying barman", an imaginative extra to help pull in the punters.

Marc has worked with Virgin for more than three years, creating menus for the Heathrow Clubhouse and training staff in how to make the perfect cocktail. "They mix some of the best in London in the Clubhouse," he asserts. But the most enviable part of his job must be this gig, jetting off once a week, six months of the year, to add "a bit of theatre" behind the bar in upper class.

He serves cocktails with a flourish to the airline's premium passengers and, if asked, will tutor them in how to make the perfect martini, Bloody Mary or whatever their favourite drink is. It's a more than enjoyable diversion on a long-haul flight.

But Marc doesn't just mix up the standards. He carries a larder of curious ingredients to liven up spirits – both bottled and human. Out of his hand luggage he produces fruits, bags of herbs, scented teas, even condiments and preserves (in 100ml bottles, of course).

"Do you like marmalade?" he asks, sluicing out his Boston shaker – half glass (to see what's going on in the mix) half metal (to prevent transferring body heat). Before I have the chance to say the desired "no", he's gathering together some light orange marmalade from the breakfast service, Cointreau, fresh lemon juice, Bombay Sapphire and sugar syrup.

As he works his magic, mashing together the ingredients with a long multi-pronged tool called a muddler, he reveals a few random secrets of the mixologist. Always fill the glass with ice – double-frozen to prevent watery drinks – and ensure the water source is pure. Don't think a big slug of spirit is essential for a successful cocktail, generally 35ml is the perfect serve (Marc's remit includes promoting responsible drinking). Don't just add a slice of fruit for citrus flavours, squeeze the juice and the oils from the peel of a lime/ orange/lemon. Clap herbs in your hand before adding to release the fragrance. And never, ever shake a martini, always stir – shaking dilutes ice by 40 per cent, only half as much if you stir.

Job done, he hands me the finished marmalade martini and a soldier of toast. Ta da! It's a delicious concoction with an unmistakable kick of marmalade. And while it could be argued that I'm open to any taste that comes in alcoholic form, to elicit a positive response from me about that revolting conserve is remarkable.

But Marc's got an even better trick up his sleeve which reveals the increasing use of science in the cocktail world. He asks a steward to get him one of the bags of dry ice that are used to keep drinks cool on board. Meanwhile, he mixes up a berry coulis from raspberries, blackberries and blueberries, which is then strained, before cranberry, lemon juice, sugar syrup and gin is added. Finally, he smashes up the dry ice in its bag before pouring it into the glass. The freezing smoke billows forth as he continues to whip the contents like some mad professor in a laboratory as they solidify into a sorbet.

Never mind all this fancy stuff, can he make me a palatable cocktail with my two favourites, gin and champagne that I can make at home? He suggests a Southside and mixes some lime, mint, sugar syrup and gin which he pours into a flute, finishing it with champagne. The final touch? A rosebud and a sprinkle of gold dust. Now that beats a warm bottle of Pommery from the trolley any day.

...or raise a glass of this cheeky little rosé

This champagne's bubbles aren't making my nose tickle – it's far too refined for that. The fizz is, in fact, a fraction subdued, but the taste has changed little at 39,000 feet to what it was at five feet. Because only 30 minutes before I'd been wine tasting in the Lufthansa lounge at Munich airport.

Markus Del Monego fluttered over glasses, pouring, sniffing and gazing at the colour until his crescendo of gestures ended with a cherubic smile and a glass in my hand. Del Monego is a master of wine and a master sommelier – the first to hold both awards. He chooses four and a half million bottles of wine annually for Lufthansa.

From being the place where winemakers used to dump unwanted plonk, airlines have improved on-board wine lists till they resemble the cellars of a Michelin-star restaurant. The principal challenge is the taste difference. "Cabin pressure does strange things to your senses," says Del Monego. "You lose a third of your sense of smell – few wines have a good nose – but your tastebuds also distort the body of the wine.

"If acidity or tannins are present they are enhanced, if there is plenty of sugar or an alcohol taste that is lessened." With all this to take into account, Del Monego points out that "a good wine is maybe one that isn't that good on the ground".

A few weeks later I'm at Heathrow for a 10am meeting in a white office where strip lighting reveals rows of bottles, their labels covered and layers deep, lining two sides of the room. Jancis Robinson, the wine critic, and Peter Nixson, British Airways' chooser and buyer of wine, are already hard at work sluicing and spouting like the hardened residuals from an office party.

"Jancis and I do two tastings a month just for BA alone," says Nixson, "but then we have probably a tasting or two a day on top of that." Add regular trips to wineries from Argentina to Australia and back again and it shows this dynamic duo are quaffing mad.

Nixson confesses that his own blind tasting in the air resulted in an English wine being chosen as best. Sadly, this couldn't possibly finish on an airline wine list. A vintage is needed in such volumes that supply is a primary issue. "We check out the quantity that we can get before tasting," says Nixson. BA uses roughly 460,000 cases of wine a year (5.5 million bottles).

Today they are tasting Rhône Valley reds and will probably choose one or two out of the 100. "You look for an obvious appeal," says Nixson, "because the palate on board is dried out. The wine will be cooler than it should, so I want lots of fruit."

"Did you get any oxidisation on 16?" he asks Robinson, who replies, "I've written down 'animal'." They stare at each and nod.

They choose a Gigondas for me to taste which, for commercial reasons, I can't name, but it was truly gorgeous, just the sort of warming, spicy and fruity Rhône that I love. I can't think of a better way to spend a Tuesday at Heathrow. Kieran Falconer