not everyone has a cargo aircraft/subsidary.

you use whatever plane you have. some airlines decide to remove seats to carry more cargo, but that's additional cost/certification and you cant carry passengers until you undo the work (while you could use this plane for passengers)

https://www.businesstraveller.com/fe...nes-for-cargo/

also, it depends if you hit the weight or volume limit first - could be carrying heavy machinery/parts (extremely urgent, $$$ of dollars down when machine is down) and you cant carry anything else despite being half empty


some airplanes just put light boxes in between the seats (eg PPE)
https://paxex.aero/converting-to-car...-covid-19-era/