Akin to the thread of flying to/from a now-closed airport, how about flying non-stop (or at least direct) between two airports that are now both closed?

I flew out of SIN Paya Lebar as a child so the most notable and obvious would be xSIN - xHKG (KaiTak), and somewhat late SIA-xCAN. Direct but not non-stop, once LH 707 xSIN-xMUC (not sure where the tops were but I imagine BAH was one of them).

Not closed but renamed, I've also flown non-stop (of course) xSIN to xKUL (now SZB) and xBKK (now DMK), and also xKUL to xJKT, and probably xKUL-xBKK.