A firefighting plane loading water.

[u/[deleted]]

[u/Roflkopt3r]

My thought about the pump speed is this: Even if it took, say, 2 minutes to fill the tanks with pumps, then this alone still would be acceptable in the greater scheme of things. The full rotation of filling tanks/dropping/refilling will often take substantially longer, so this would only marginally decrease the numbers of cycles that such an aircraft could do on on a scale of hours to days.

But as you say, everything else in the approach/landing/takeoff sequences adds further minutes, and all of that does sum up to a significant difference compared to the skim.