As they powered down the aircraft on the tarmac of Barcelona's El Prat international airport, the personnel disembarking from a sleek Gulfstream jet would have looked little different from the other tired and hungry aircrew passing through.

But as they took off the next morning for Washington on the final leg of a curious odyssey, a glance at their recent layovers – Riyadh, Amman, Bucharest – would have given a clue: this was no ordinary plane.

According to documents that have emerged from a seemingly obscure legal squabble in upstate New York, the jet, Gulfstream N85VM, formed an integral part of the fleet of private aircraft that helped the CIA to run its clandestine programme of extraordinary rendition after the 9/11 attacks.

The records offer an unprecedented insight not just into the movements of the Gulfstream jet, but also into how the rendition programme was subject to a culture every bit as corporate as other initiatives undertaken by a US administration keen on outsourcing the affairs of state to the private sector. Cheaply, if possible.

"They were trying to control their funding or their spending, and they wanted the cheapest aircraft to fulfil a mission," said Don Moss, the owner of the aircraft broker Sportsflight, which arranged for another company to put the aircraft at the service of Dyncorp, a private military company acting on behalf of the CIA.

Moss made the remark during cross-examination in a New York court case generated by a legal dispute between his company and Richmor Aviation Inc, which initiated the proceedings to recover payment it claimed it was owed.

The Gulfstream IV executive jet was made available at a cut-rate $4,900 (about £3,000) an hour. Crew members were paid $800 a day, according to invoices submitted to the hearing. They would submit expenses claims for meals (pdf) – deli sandwiches at $19.95 a time, bottles of wine at $39.95 each – and stay in expensive hotels: $391 a head for one night's stay in Barcelona in January 2004, for example; $277 each for accommodation at Shannon on the west coast of Ireland the following August.

Before each flight an administrative officer at the US department of state would hand over a "to whom it may concern" letter (pdf) which made clear that their mission offered "global support to US embassies worldwide". They were warned, however, that they needed to provide detailed explanations on their invoices, as Dyncorp "operate very much like the government" and would reject any claims considered too vague.

Despite the attempts to keep costs down, the invoices submitted to the court as evidence show that some rendition operations were eye-wateringly expensive. In November 2002, for example, Gulfstream N85VM made a six-day round trip from Washington, taking in Guantánamo Bay, Shannon, Dubai, Kabul, and Edinburgh (pdf). Richmor's bill was for $240,643 and 95 cents, including catering, landing fees and the cost of an additional crew member.

Another operation that month, which saw the Gulfstream fly from Washington to Kabul via Shannon and Dubai, (pdf) and return via Dubai and Luton, north of London, resulted in a bill from Richmor for $198,930 and 30 cents.

Bizarrely, given the purpose of the flights, Richmor was expected to meet US federal regulations, meaning rendition aircraft (pdf) were designated as drug-free workplaces, to be operated only by companies that took affirmative action to employ workers with disabilities.

The real value of the documents is the way they allow the most comprehensive and verifiable picture to date of the CIA's so-called "ghost planes" to be mapped out. In the past, White House administrations under both George W Bush and Barack Obama have moved to ensure that details of the programme did not leak out from court proceedings.

However, a lawyer who acted for Richmor's president, Mahlon Richards, told the Guardian that there was no such intervention on this occasion.

"What happened here was that Richmor Aviation entered into a contract with Sportsflight to provide rendition flights for detainees and after I got involved in it and I saw the various invoices from Richmor that were submitted to Sportsflight it was amazing to me that no one from the United States government ever said boo to me about any of this," said William Ryan, of the law firm Tabner, Ryan and Keniry. "So I just went about prosecuting the case for the client."

Jeffrey Heller, a lawyer at the firm Somer and Heller, which acted for Sportsflight, said that it was "nothing more than an air travel broker". "I don't believe that Don Moss had any knowledge, specifically in advance, of what these flights were going to entail," he said.

"I don't think they knew there was going to be these rendition flights.

"Sportsflight brokered the contract and then brokers the availability of air travel, so Richmor then has these planes ready and then the government agency goes directing to Richmor to book these flights, so Sportsflight is kind of out of it. They don't necessarily know where it's going, when and who is getting on."

Gulfstream N85VM has already been identified as the aircraft that rendered Hassan Mustafa Osama Nasr, an Egyptian cleric known as Abu Omar, after CIA agents kidnapped him in broad daylight in Milan in February 2003 and took him to Cairo. Through close examination of the invoices it is possible to identify other rendition flights in which a number of high-profile al-Qaida suspects may have been rendered.

In August 2003, for example, Richmor submitted an invoice for $301,113 for eight flights over three days that took the Gulfstream to Bangkok, via Alaska and Japan, on to Kabul via Sri Lanka, and then home again via Dubai and Shannon (pdf). This operation appears to have been the rendition of Encep Nuraman, the leader of the Indonesian terrorist organisation Jemaah Islamiyah, better known as Hambali. He had been captured in Thailand shortly before the aircraft set off.

The court heard that in October 2004 the aircraft's tail number was changed to N227SV after the US government discovered that its movements were being tracked. The following March the aircraft was publicly linked to the Abu Omar rendition. Phillip Morse, the aircraft's ultimate owner, said he was stunned to discover how his plane was being used.

Later that year, businessmen involved in the rendition programme spotted a new opportunity after a number of companies that operated the CIA's own fleet of aircraft – which also operated rendition flights – were exposed in the US media as agency front operations.

Moss wrote to Mahlon Richards at Richmor: "This has changed the whole posture of the end user, to the extent they are reluctant to operate their own aircraft (pdf) and have elected to ground certain equipment indefinitely. We hope this can be to our benefit."

But the happy days of deli sandwiches, $40 wine and $4,900-an-hour fees were about to come to an end. As a result of media investigations around the world and parliamentary inquiries in Europe, the truth about the rendition programme – and the fate of its victims – was slowly becoming clear.

Soon Morse and his family were reluctant to climb aboard their own jet. "They were afraid to fly in their aircraft because of all the publicity about their particular airplane," Richards told the court.

Italian investigators began an investigation into the kidnap of Abu Omar that ultimately resulted in the conviction of 23 Americans, all but one of them CIA agents, who were tried in their absence. Two Italian intelligence officers were also convicted. The former head of the CIA in Milan, Robert Lady, was given an eight-year jail sentence.

By October 2006, Richards was writing to Moss to complain that his company was suffering negative publicity (pdf), losing business and receiving hate mail. The Gulfstream's crews were afraid to leave the country. "In the future, whenever the name 'Richmor' is googled this will come up. N227SV will always be linked to renditions. No tail number change will ever erase that and our requests for government assistance in this matter have been ignored."

Additional reporting by Sarika Bansal