Finland’s 64 F-35A jets face expensive retrofits as the critical Block 4 upgrade slips to at least 2031, five years behind the original schedule. The €8.38 billion deal, signed in February 2025, specified Block 4 configuration for deliveries starting 2026, replacing the aging F/A-18 Hornet fleet by 2030.
GAO reports confirm the Pentagon rescope trimmed Block 4 from 66 capabilities, deferring engine upgrades like the F135 core needed for post-Block 4 systems until 2033. Finland’s aircraft, arriving in Block 4 trim, will require full conversions later, driving up sustainment costs beyond the deal’s €777 million infrastructure and €824 million weapons allocations.
Initial training begins in the U.S. this year, with operational handover in Finland from 2026. Local facilities include Patria’s forward fuselage line in Yamsa and Nokia spaces for F135 engine assembly turning to overhauls.
This mirrors Norway’s 52 F-35s, each projected at $769 million lifetime cost versus $110-130 million per unit acquisition. Supply chain strains and cooling system complexities, vital for new electronics, exacerbate delays across the 3,100-jet program through 2035.
For Finland, the slippage threatens Hornet replacement timelines and budget, forcing interim capabilities while locking in long-term dependency on Lockheed Martin upgrades. Compared to Saab Gripen E/F at $138-146 million per aircraft, F-35’s stealth and sensor fusion demand higher sustainment investment amid industry production backlogs.