The Israeli air force wants to increase the operational range of its future fleet of 100 Lockheed Martin F-35 Joint Strike Fighters by adding new external fuel tanks that are already being developed by domestic companies.

Elbit Systems subsidiary Cyclone Aviation is offering to supply external tanks to be carried on the F-35's under-wing hardpoints, while Israel Aerospace Industries plans to produce conformal fuel tanks for the Israeli fighters.

Israel's air force recently completed the design of a unique F-35 version optimised for its mission requirements, but further details remain highly classified.

Under current plans, Israel will sign a letter of agreement in 2009 to advance a multi-year purchase of the F-35, which local sources say will be launched with an order for 25 aircraft for delivery from 2014, plus options on a further 25.

In a further bid to extend the range of its strike aircraft, Israel's Boeing 707 tanker-transports will be equipped with Honeywell-supplied glass cockpits incorporating new communications equipment, six multi-function displays and a global air traffic management system.

The work forms part of a wider modernisation effort, which will also see the type's IAI-produced refuelling boom replaced with the design used by the US Air Force's Boeing KC-135s.