Strategy Page has more on the increasing spendiness of the F-35 program, especially the part the Navy is most concerned about:
Denmark has decided to wait, until 2014, to decide what to replace its elderly F-16 fleet with. Meanwhile, 18 of the F-16s will be retired. But the other 30 will be refurbished so that they can continue to operate for the rest of the decade. Denmark had wanted to replace the F-16s with F-35s. But the F-35s keeps getting delayed (now more than two years behind schedule), and is becoming more expensive (nearly a hundred percent over budget). The Danish F-35 buy is no longer a sure thing. The delays have lots of users concerned. The U.S. Navy has been nervously watching as the costs of the new F-35C and F-35B carrier aircraft versions go up.
It comes down to this. Currently, it costs the navy, on average, $19,000 an hour to operate its AV-8 vertical takeoff and F-18C fighter aircraft. It costs 63 percent more to operate the F-35C (which will replace the F-18C) and the F-35B (which will replace the AV-8). These costs include buying the aircraft, training and maintaining the pilots, the aircraft and purchasing expendable items (fuel, spare parts, munitions.) Like the F-22, which recently had production capped at less than 200 aircraft, the capabilities, as superior as they were, did not justify the much higher costs. The F-35, at least for the navy, is headed in the same direction. The navy can go ahead with the more recent F-18E, and keep refurbishing, or even building, the AV-8. Politics, and lobbying by the F-35 manufacturer, will probably keep the F-35 headed for fleet service, no matter what the cost.
Another ally watching the F-35B costs rise with trepidation is the Royal Navy, whose aircraft carriers are not able to handle conventional aircraft (even the two large carriers under construction won’t have catapults for launching non-STOL planes). Earlier posts on the Royal Navy’s carrier worries here and here.