"the jet (which is easily replaced)"
Since for some reason we in the UK only own 15 F-35s so far, if they are easily replaced, why don't we hide those 15 under a tarpaulin for a bit, and 'replace' them?
I suggest that purely in cost terms, F-35 pilots are currently easier to replace than F-35s. But it wouldn't do to be caught planning anything based on that idea; it wouldn't do at all.