Two men alone with their thoughts, thousands and thousands of feet above the world.
Earlier this week, both of Ireland's most recognisable captains were suspended somewhere in the air en route to the latest staging post of their remarkable sporting journeys.
One man leaving home; the other, returning.
In Brian O'Driscoll's case, a fourth and final World Cup beckons, a last chance to fulfil the only remaining blemish upon an otherwise stainless reputation; for Robbie Keane, his latest -- potentially one remaining -- opportunity to pitch up at a major international football tournament.
One man beloved by so many of his countrymen; the other, adored and abused by the public in equal measure.
Both are leaders of men in their national jersey, but while one invites nothing but enthusiastic approbation; the other is occasionally assailed by spite and begrudgery. Theirs is an extraordinarily polar existence.
It remains an enduring source of regret that this is so.
Before he led his Ireland squad on their arduous 48-hour trip to New Zealand for this month's World Cup, O'Driscoll reflected with aching regret on the lack of fulfilment hitherto provided by rugby's global showpiece.
"I don't want to finish my own career not having achieved on the biggest stage," said O'Driscoll.
"There's the motivation for me. People have different motivations, but that's mine. I want to finish my last World Cup on a high."
As one, a nation pitifully pined for their captain, sharing his disappointment and willing him to tick off the one remaining honour that has eluded the greatest rugby player ever produced by this country.
And so he departed with the unconditional goodwill of a nation speeding him.
This afternoon, as Robbie Keane pitches up by the sea in Malahide, we will once again ask Keane of his desire and longing to replicate his one appearance at a major championship and he will once again dutifully and politely reiterate that natural longing to relive the heights of 2002.
But not all of the housewives will longingly tip their eyes to heaven when they hear his words, not all sporting ecumenists will proffer their unqualified support to his aims.
Ennui will joust with enthusiasm among his wider audience.
Would that one could give an adequate enough explanation as to why.
Perhaps the answer can be found within the personalities of both men. O'Driscoll's is popularly available, easily discernible; Keane's is almost wholly invisible, publicly distant.
They are both in their early 30s, still operating at the peak of their powers in a green shirt and they each boast celebrity wives -- and yet the chasm between their share of the public's popular acclaim is yawning.
True, there is a class issue at work; both men's sports historically accrue the majority of their players and supporters from different social backgrounds. But this can hardly be the crux of the matter. Paradoxically, the riches available to both players differ wildly -- Keane's massive salary dwarfs that of his fellow Dubliner by a multiple of at least 10.
The sporting culture in which he has thrived, the English Premiership, is a garish entity far removed from the grounded normality of the Leinster or Ireland rugby scene.
And therein lies the rub, perhaps.
O'Driscoll has remained of us, it appears to all; Keane, it is routinely charged, has not.
Perhaps indicted purely by Premier League proximity, Keane's persona has -- in the eyes of some -- become inextricably linked with all that is distasteful about English soccer, however unfair that may be to him.
Unlike O'Driscoll, we have never got to know the personality behind the lavish football boot endorsements.
It didn't help that in a decade when Irish rugby became sexier than ever, Irish soccer became seedier than ever.
Sport reveals character, it is said. Sadly, Keane has chosen to reveal precious little of his through the years.
Returning to Moscow, as Ireland will next week, recalls an informal meeting with Keane on Ireland's last visit there nine years ago, just as the curtain was coming down on the Irish soccer team's once unqualified relationship with its supporters.
Despite the recent memory of Saipan-inflicted trauma, Keane revealed much of the character and ebullience related so often by so many of his team-mates and associates in the intervening years.
Yet Keane has since chosen to keep that side of himself hidden all the while, such that the significant swathe of the public who remain unconvinced of his every movement and only know him through exaggerated penalty appeals, or that cringe-inducing 'Late Late Show' appearance.
While Keane the professional footballer's unswerving loyalty to Ireland remains unquestioned, and his goalscoring record demands respect, Keane the human being remains as misconstrued as ever.
Now that he has decamped to what Emmylou Harris once described as a "whole new world," Keane has been pilloried from all quarters of opinion, from bar stool to news print, for supplanting one hotbed of vulgar excess for another, albeit sunnier.
He hasn't cared before for these opinions and, as he made it clear last weekend when clearly cajoled into speaking from his new Los Angeles home, he doesn't particularly care now either.
Today, he will be as occasionally charming and witty as he has been whenever being presented to the public as Irish captain, particularly when alongside Giovanni Trapattoni.
And, over the next five days, he will be an integral, indispensable factor in propelling Ireland's attempts to qualify for another major tournament. And with it the chance for the country to fall in love with its national soccer team once again.
Whether they will all fall in love with Robbie Keane is another story entirely. Sadly, it is much too late for that to happen now.
"To know him is to love him," says the old song. Such a pity so many never got the chance.