In depth: Julian Assange and Edward Snowden - enemies of the state take flight

By seeking refuge in limbo while fleeing the most powerful nation on Earth, they exemplify the romance of the contemporary fugitive

Five hundred years ago, he might have found himself in a church. In the middle ages, Edward Snowden, seeking sanctuary from charges of treason, would have thrown himself on God's mercy. Once across the holy threshold, he would have been untouchable by earthly justice.

God is a bit weaker now, and so today's canny fugitive takes a more prosaic approach. If there is no higher law, he needs a lawless zone instead. If he is Edward Snowden, he heads for the airport. If he is Julian Assange, he heads for the embassy. His best hope is not heaven. It is limbo.

Why do we find Snowden and Assange such fascinating figures? They are postmodern outlaws, frustrated nomads who have given up the comforts of an ordinarily rooted life. They are compelling because their predicament is both horrifying and seductive. Most of us need our roots too much to embrace the dislocated life that they have come upon. And yet, even as the internet and affordable travel make the world smaller, the romance of the wanderer remains – and in particular of the wanderer who sets himself against powerful and impersonal forces.

But these would-be wanderers are confined. Grim though Assange's hiding place sounds, it is at least on a human scale. What of Snowden's? At least until new offers of asylum from Venezuela and Nicaragua come good, he is at Moscow's Sheremetyevo Airport, "airside", in the "transit zone". These terms make me uneasy. They evoke something alien. In the "transit zone", where a man who would elsewhere be swiftly arrested can linger seemingly as long as he likes, the tenuous nature of our laws and nations and conventions is made explicit. You'll know what it's like if you've ever stood with a foot on either side of a border and felt – nothing. One almost expects there to be an accompanying physical sensation, evidence that our systems are tattooed into the ground. But there's not. The border is arbitrary. The political map is just a picture with lines drawn on it.

Sure enough, experts have reminded us this week that even the special status of the transit zone is entirely subject to the whim of the country in which it is based. After a year, at least Assange can feel confident in the international treaties that secure the status of an embassy. The privileges of Snowden's life airside, on the other hand, might be withdrawn at a moment's notice.

Although privileges may be the wrong word. The cage of Sheremetyevo does not sound particularly gilded. Snowden flew into terminal F from Hong Kong on 23 June, shortly after his passport was revoked by the US authorities.

Terminal F is described by a reviewer on airlinequality.com as an "awful prison", but it is at least connected by a mile-long walkway to terminals D and E, which are said to be better appointed. Enterprising journalists who have flown into Sheremetyevo in the hope of finding Snowden have so far failed to do so. This may be because of a relatively unusual feature of the airport, the airside wing of the Novotel hotel, where passengers in transit without Russian visas are permitted to stay.

Some have speculated that the fugitive could be holed up in one of the hotel's spartan rooms, awaiting the call from a friendly nation to leap on the next plane out of Moscow and return to a slightly more normal life. An AP reporter who spent a night there in search of Snowden called every room he could, to no avail; his efforts to seek him out in person were thwarted by the security guard stationed outside his door. He could be in the hotel, yes. But he could be in the airport's detention quarters, so infamous that they once featured in the UNHCR's guide to the problems facing the world's refugees; he could be paying $20 an hour for a spot in a VIP lounge; he could be browsing the duty-free matryoshkas, somehow unseen by the world's press; he could be somewhere else altogether. For the time being, at least, he is out of reach.

The uncertainty over Snowden's whereabouts only makes the question of what his life might be like at the moment more tantalising. If he is Lennon's "Nowhere Man" – "sitting in his nowhere land, making all his nowhere plans", someone who "doesn't have a point of view, knows not where he's going to" – the airport is maybe the quintessential example of what have been called "non-places".

In his brilliant book The Global Soul, the travel writer Pico Iyer describes it thus: "The modern airport is based on the assumption that everyone's from somewhere else," he says, "and so in need of something he can recognise to make him feel at home; it becomes, therefore, an anthology of generic spaces – the shopping mall, the food court, the hotel lobby – which bear the same relationship to life, perhaps, that muzak does to music."

Spend too long in a non-place – which could just as well be a shopping centre or a service station or a hotel – and one might very well become a nowhere man. It is hard to fathom the state of mind of the Iranian exile Mehran Karimi Nasseri, who found himself in the no-man's-land of the departure lounge at Paris's Charles de Gaulle airport for fully 18 years; or that of Ram Charan, a successful business consultant who lived entirely on planes and in hotels until the age of 67, and whose only concession to normality was a weekly parcel of dirty laundry sent to an office in Dallas. How would it feel to live that way?

Last week I went airside at Heathrow's Terminal Five, trying to imagine it for myself. Terminal Five is so huge that you could fit three Empire State buildings on their sides into the luggage hall alone. It took 18 years, 20,000 workers and £4.3bn to build. And yet its salient characteristics are the same as those of any major airport anywhere. As I drifted through security, the epic, gentle curve of the 40-metre high roof, almost so high that you forget it's there, seemed oddly comforting. After you've been swallowed up at the gate, there's no view back. I was reminded of my childhood affection for Star Trek, mostly founded on how comfortingly enclosed the Enterprise seemed to be. I was reminded of the inside of a whale.

As I wandered around, though, and tried to imagine what it would be like to spend any sustained amount of time here, my sense of the place changed. The logic of the design is impeccable as a means of funnelling the maximum number of travellers through the maximum number of shops before they head for the skies, but it is not terribly sympathetic to human beings. My thoughts of Star Trek were displaced by Wall-E, and that movie's corpulent, hoverchair-bound consumers, carted around their spaceship from meal to meal, never fully conscious of the life they were missing, always dislocated.

The people with the best idea of how to live in the terminal are, of course, the people who work there. In this cavernous dome, they carve out little nooks for their breaks, away from the crush of the main drag, by cramming chairs shaped like satellite dishes under far-flung staircases. "It's sort of hard to think your own thoughts in here," one shop assistant said, fiddling with her iPhone on a short break from her duties in the perfumery. "It's so hectic. You just want a bit of space."

It seems a strange phrase, when space is exactly what there is too much of. Where would she sleep if she was spending the night here? She thought for a bit, and then settled on the children's play area, a sort of inhabitable Rubik's cube, and about the only enclosed area to be found. "You could get a proper night's sleep there," she said. "It'd be quite cosy."

Whether cosiness is important to Snowden, who, it has been said, can be happy anywhere he can get online, is hard to know. If new offers of help materialise, he may not be at the airport for very much longer. Assange, meanwhile, must be losing his will to stay in a prison of his own construction, even if the alternative is one of rather less hypothetical limits. But perhaps such people last longer in these circumstances than the rest of us might.

Uniquely modern fugitives, they are taking refuge in uniquely modern spaces. It's not a coincidence that they are also both men of the internet, a space like the airport terminal or the embassy where the conventional rules don't apply; a space of all nations, and of none; a space where your home is simply the first page you land on, a jumping-off point for a journey into the unknown.