The F-35: Known Unknowns On Cost, by David Archibald.

The USAF’s Lt. Gen. Jerry Harris is quoted as saying … that the cost of operation differed based on production block and usage, but was approximately $50,000 per hour.

That US$50,000 per hour figure is a reliable number to use when estimating the cost of operating the RAAF’s F-35s. At the current exchange rate that is $70,000 per hour to get something that will be capable of taking off 60% of the time. To keep a pilot proficient takes 20 hours of flying per month so that will be $1.4 million or close to $17 million per annum. Flying less than that means that pilots start to lose the ability to fly the aircraft itself, let alone use it in battle. The US Marine Corps started having a higher aircraft accident rate in the last couple of years because their pilots weren’t getting enough time in the cockpit. …

In comparison to the $70,000 per hour that the F-35 will cost, the Gripen E is likely to cost about $10,000 per hour while being a much better fighter aircraft, ground attack aircraft and everything-else aircraft than the F-35.

The F-35 might be a better AWACS-type platform, but if it can’t be relied upon to get in the air then it is not much use for anything. If an aircraft type has 50% availability then you need at least three of them to get a 87.5% chance that you can get at least one of those three in the air.  That is how bad the F-35 is.