flightleader - these airways may be under SIN WMFC FIR but Indonesia CAA permission is required because those airways overfly Indonesia land-mass i.e. islands.On 14 Jan 2019 an Ethiopian Airlines flight was intercepted by 2 Indonesian Air Force F16's for flying across Indonesian airspace without permission. The aircraft was initially supposed to operate from HAAB/Addis Ababa to VHHH/Hong Kong, but was modified at the last minute to route via WSSS/Singapore instead, to make a delivery of Rolls-Royce Trent 1000 engines.
The Ethiopian Airlines aircraft was intercepted forced to land at WIDD/Batam Island – which lies right in the middle of the chunk of airspace controlled by Singapore.