In-flight ISP Tenzing is increasing the speed of its connections and adding wireless connectivity in an effort to fend off competition from Boeing's high-profile rival service.

The upgrades to Tenzing services, in use by several US and international airlines, may start a battle between two very different models of in-flight data access, according to industry observers.

Boeing's Connexion, which offers Wi-Fi Internet access on planes, is to see its commercial launch later this month on long-haul Lufthansa aircraft, but installation has been estimated to cost around $1 million (£550,000) per plane. By contrast, Tenzing - which is part-owned by Airbus - offers a more limited service, but costs airlines very little. It has already been deployed on 900 aircraft.

The current Tenzing service, rolled out over the past year by Cathay Pacific, Continental Airlines, United Airlines and US Airways, allows users to send and receive email from their standard accounts using a laptop, a service for which experts say there is strong business demand. It uses the in-flight telephone infrastructure already built into many planes, which means that in most cases, airlines have only to install server software to get the system running.

The service costs airlines little, but it is not seeing heavy use, as Tenzing admitted in a recent Wall Street Journal report. Among its limitations are the need to connect via a RJ11 telephone cord, a sluggish 128Kbit/s connection, lack of virtual private network (VPN) capabilities and surcharges for large emails and attachments. By contrast, Boeing's Connexion offers 5Mbit/s download and 1Mbit/s upload and full Internet access including VPN, for user prices comparable to Tenzing's.

Now, in an effort to make its services more attractive to business customers, Tenzing has said it will boost speeds as high as 1.7Mbit/s for both uploads and downloads, while Emirates is about to launch the first Wi-Fi-enabled Tenzing offering.

Emirates is billing its in-flight email service, due to launch this month, as the first commercial Wi-Fi service on a plane - though there is a chance Lufthansa may beat Emirates to the punch. Emirates will enable both Wi-Fi and wired connections on a new Airbus A340-500 aircraft, later progressing to its entire fleet. First and business-class passengers will also have RJ45 Ethernet jacks and laptop power sockets.

Wireless connectivity is not just a matter of convenience; business users may start to expect and demand it, according to Robin Duke-Woolley, director of technology consultant E-principles. "Wi-Fi is going to become a standard feature in most new laptops, and when that happens the desireability of Wi-Fi on planes will be very high," he said. "I think the Wi-Fi alternative is where the market will end up. The question is, does (the cabled method) offer a useful starter to the market?" The Emirates deal appears to show that Tenzing is pushing its services ahead, he said: "They may be covering themselves."

Fast connection speed is important to business users, who tend to download large numbers of messages and big attachments, analysts said. Tenzing recently announced a deal to bring in a faster connection speed on Iberia's long-haul fleet of A340-600 and A340-300 aircraft, beginning in October of this year. A new service from satellite giant Inmarsat will mean symmetrical speeds of 864Kbit/s or 1.7Mbit/s, starting in early 2006, Tenzing said.

Inmarsat's Broadband Global Area Network (BGAN) satellites, scheduled for launch later this year, will offer 432Kbit/s channels, and airlines will be able to buy two or four bonded channels for speeds comparable to terrestrial broadband, the company told Wi-Fi Network News. Since most international airlines are already equipped with Inmarsat equipment for telephony and cockpit communications, the upgrade from 128Kbit/s to 864 Kbit/s will be simple and inexpensive, the article explained.

The transciever needed for the faster service costs less than $100,000, according to Tenzing. User prices will benefit from the system, with Tenzing planning to drop surcharges for large emails.

The VPN stumbling block may prove more difficult to overcome. Industry experts were divided over the immediate importance of VPN in the air: many business travellers can access Exchange or Lotus Notes communications via a Web browser or POP3, but VPNs are now taken for granted by many businesses. "A VPN does seem necessary for business users," said Mark Darby, managing director of Aviation Strategy.

Even if VPNs are not always needed for basic corporate email, business users often need remote access to the corporate intranet, noted Duke-Woolley. "For intranet access, a VPN is very important, and any thought of doing transactions would require secure access," he said.

Tenzing's current workaround is to make VPN arrangements with individual companies, setting up a secure gateway through Tenzing's proxy server. However, like many aspects of Tenzing's service, this is not the most convenient arrangement for business users, Duke-Woolley said: "It's not like just being able to dial up, is it? I'm sure it works, but flexibility is quite important."

If Tenzing's efforts seem irrelevant in the face of Connexion's imminent launch, the more limited service has at least one advantage: it is available now. Lufthansa's first Wi-Fi-enabled plane may be launching this month, but the rest of the carrier's planes will not be equipped until sometime in 2005, Lufthansa has said, and other Boeing customers will not even begin outfitting their planes until later this year.