He produces jugs of non-alcoholic beer, which the Kuwaiti spikes with vodka.  Our pilot opts for a Coke.  The Frenchman sits apart with the Danish Member of Parliament.
'When I first arrived in Afghanistan there was such optimism,' I overhear a CARE worker tell the Nigerian.  She is sincere, passionate and from Charleston.  'People would open the doors of our cars just to shake our hands.'
'In our education programme we had former Taliban fighters studying Grade 3 maths alongside eight-year-olds,' he replies.
Soldiers play cards, drop quarters into the jukebox, look at each other and smile when they think we aren't looking.  Their civility brings to mind blue-collar shift workers more than fighting men and women.  None of them seems scarred by war, except for the commandos in their beards and Afghan patou scarves.  Their eyes, dim with exhaustion, never flicker from the wide screen television.

I'm talking about my journey, and the Sixties' dream of building a better world, when the lieutenant asks me, 'You aren't an aid worker, are you?'
I tell him what I do and around me the conversation stops. 

'You're a what?' asks the Danish MP.
'A travel writer,' I repeat.
I half-expect to be asked to leave by the back gate.  Or to be marched away by a dozen angry humanitarians for misuse of the UN.  But instead the vet says, 'Where have you been?'
' Most of Europe and America,' I reply.  It's the usual question.  'Australia and the Pacific, South-east Asia, Burma...'  I tend to mention the places which will interest an audience.
'Burma,' gushes the MP.
'I bet Burma was amazing,' says the vet.
'It's a military dictatorship,' I remind him.
'What a perfect job,' says the CARE worker.  'Any room for me in your suitcase?'
Serious discussions about appeasing hatred, 'frag' wounds and the balancing of US military power with European altruism are forgotten.  All the politician wants to know about is cruises on the Irrawaddy River.  The vet asks me to recommend a bargain Manhattan hotel.  The Nigerian has a dozen questions about air miles.  I tell them what I'm writing about.
'The hippie trail?' laughs the MP, moving to our table.  'I wouldn't be here now if I hadn't hitched to India in 1967.'
'My older brother did it too,' cuts in the captain.  'I was so jealous of him.'
Even the Frenchman takes an interest.  'The Sixties was the journey from innocence to experience.'
'Another beer?' asks the Lieutenant, a great grin spreading across his face.
Then someone selects the 5th Dimension on the Wurlitzer.

'We had a Sixties evening last month,' one of the book club engineers calls above the music.
'The junk's still back here,' says the bartender. 
The vet stands up to take the cardboard box and unfolds a tangled web of beads, bells and Beatles wigs.  He puts on a pair of John Lennon granny glasses.  The MP joins him, talking of Big Dreams and a broken-down Peace bus, stretching a plastic flower headband over her coifed head.  Then an engineer pulls a leopard-spot miniskirt up over her work overalls.  I can't imagine how all this stuff reached Afghanistan again, except aboard a USAF C-130, but suddenly everyone is at the bar wearing buckskin, paisley shirts and brocade Carnaby Street waistcoats.  Even the commandos look towards us, though they keep themselves apart.  But like burnt-out rock 'n' roll veterans they fit right in too, especially in their Afghan chapans.

'When the moon is in the Seventh House, and Jupiter aligns with Mars, then peace will guide the planets...'

In the box the vet finds two volumes of poetry by Richard Brautigan – that joyous and skewed American original – and, sitting Buddha-like on a tabletop, starts reading from The Galilee Hitch-Hiker and Karma Repair Kit: Items 1-4.  He skips to Our Beautiful West Coast Thing.  '.....listening to The Mamas and The Papas...singing a song about breaking somebody's heart...I think I'll get up and dance around the room.  Here I go!' 
And he does.  The vet gets up and starts to dance.  The CARE worker and Kiwi stewardess join him, as do a couple of the engineers.  The Dane takes the Frenchman's hand and swings him onto the floor.  The Kuwaiti boogies into the throng.  I start strumming an air guitar.  It all happens in a second.  The pilot claims he's having an acid flashback.  The Nigerian leans over to shout at me, only half in jest, 'Good vibes, man.'

Suddenly we are intoxicated.  Because of our anxiety, because of the day's frustrations and especially because of vodka, the group relaxes, lets down their hair – at least those who still have hair – and allow wide-eyed, youthful exuberance to sweep aside our suspicions.

'...No more falsehoods or derisions...'

Do-gooders and door gunners spin on tiptoes.  Aid managers and Sergeants First Class sing along to Aquarius.  Our gestures become animated, our conversations flow.  A commando holds a single plastic flower in his fist.  A PsycOps corporal with cinnamon-brown skin tells me, 'Actually I'm a Capricorn.'  The poems, lyrics and gracious ideals are seductive and hypnotic, deluded and naive.  The words move our hearts and for an exquisite moment keep at bay our rational scepticism.

'...Golden living dreams of visions...'

Then four minutes and 48 seconds after it began the song ends.  The music stops.  We stand self-consciously at the centre of the tent, arms raised to the canvas roof or held out at our sides.  We slip off the wigs and rose-tinted glasses and retreat to our tables.  I hang up my imaginary Stratocaster.   Beyond the screen door the 455th Air Expeditionary Group launches an A-10 Thunderbolt II patrol into the dusk.

Magic Bus: On the Hippie Trail from Istanbul to India is published by Penguin. This extract was reproduced in Travel Intelligence .