Annoyingly the biggest plane was taken out of service this spring, partially because of liability issues after a retardent drop killed a firefighter and mostly because it was more lucrative to move freight.
https://fireaviation.com/2021/04/23/the-747-supertanker-is-c...
We badly need more of this size carrier base don what my fire fighter friends tell me, although removing fuel in winter months would solve the problem at its core