Gilmour Space Technologies is developing a hybrid propulsion launch vehicle to deliver payloads of up to 250 kg into Low Earth Orbits (LEOs). Their most recent suborbital prototype was constructed primarily using aluminium tank components. However, whilst aluminium is cheaper, it does result in a heavier launch vehicle. Gilmour anticipates that by using carbon fibre composite tanks for their three-stage rocket, they would be able to achieve a lower weight mass for their launch vehicle which will be needed for a globally competitive LEO orbital launch vehicle.
See more https://www.amgc.org.au/project/composite-wound-rocket-tanks/