On: Airlines are running out of 4-digit flight numbers

[petesergeant]

It's common in Asia, with regional affiliates like the different AirAsia, LionAir, and VietJet companies having virtually identical branding but different flight prefixes.

[konimex → petesergeant]

I can confirm for AirAsia and Lion Group, and IIRC Ryanair also do this with their UK subsidiary with different flight prefixes and different aircraft registration numbers.