OTTAWA - Senior defence officials admit they don't have a "Plan B" to deal with delays in the F-35 jetfighter program.

They claim they don't need one because recent upgrades to Canada's CF-18 mean the fighter-bombers can "easily" stay in the air to 2020 and beyond.

The Harper government, however, may still be looking for a F-35 alternative.

In the Commons yesterday Associated Defence Minister Julian Fantino told opposition parties to "stay tuned" for a response to the Pentagon's statement that the cost of the radar-evading plane would rise.

The Conservatives have been hammered in Commons over delays and cost overruns in the multinational F-35 project.

Other allies, such as Australia, have placed orders for Super Hornets -- the newer, beefed up version of the CF-18 -- to hedge against F-35 delays.

Canada isn't expected to take delivery of its first stealth fighters from Lockheed Martin until 2016.