"An increasing number of aircraft are equipped, the fear of seeing the aircraft crash is declining. It is not as expensive as was thought ...," an internal newsletter of the US's National Security Agency (NSA) enthused over the use of phones inflight in 2009 after the agency discovered it could intercept mobiles in planes flying above 10,000 feet.
Documents analysed by France's Le Monde newspaper in cooperation with the Intercept website of Glenn Greenwald and Laura Poitras show that the NSA and Britain's GCHQ planned to gather reams of information from tapping into inflight phone traffic.
Air France targeted
As early as 2005 the agency mentioned Air France in a list of airlines that would be targeted, noting that as from the end of 2003 "the CIA considered that Air France and Air Mexico flights were potential targets for terrorists".
The NSA's legal department found "absolutely no legal problem in targeting aircraft from these two companies abroad" and "they should be kept under strict surveillance from the point at which they enter American air space".
Air France first tested the inflight use of smartphones in December 2007 on a Paris-Warsaw flight.
"We began early but since then we have carried out tests continuously and today, like other companies, we are getting ready to move directly to WiFi on board," a company spokesmperson told Le Monde.
But it later told the Reuters news agency that it was suprised by the claims, adding that calls are "not possible" from its flights and that it dropped plans to make them so after the 2007 tests whose results were "inconclusive".
Not limited to terrorists
By 2009 100,000 people had used mobile phones while in flight and the NSA anticipated that hundreds of thousands would soon be doing so.
"This implies a population which goes far beyond the targets involving terrorism alone. The political or economic surveillance of passengers in Business or in First Class on long-haul flights is of interest to many more services," comments Le Monde.
The intercepts identify Pin codes and email addresses and can gather information from voices, data, SMS, Webmail, Webchat, social networks like Facebook and Twitter, travel apps, Google maps, currency converters, media, VOIP, BitTorrent and Skype.
The British also discovered that Russian company Aeroflot appeared to be facilitating interception on its flights.
Israel, Jordan, Palestine
The extent of possible snooping is indicated by other revelations published by Le Monde.
Confidential documents show that the British spied on Israeli diplomats, arms manufacturers and universities specialising in scientific research.
GCHQ also appears to have listened in on Jordanian King Abdullah's court and his chief of protocol and the country's Washington embassy and leading figures in the Palestinian Authority, as well as its delegations in several countries, including France.
Both the NSA and GCHQ refused to comment on the revelations, apart from to insist that their activities conformed with their own countries' law.