Heat absolutely does kill bacteria. Heating water for just a few minutes at 60C will kill e. coli, 70C will kill it instantly. Coffee is brewed at 90-100C.
yea wilderness survival says full boil for at least 3 minutes, more in higher altitude. While shopping for an on-demand hot water tap, I couldn't find a single one that even went up to boiling temperature, so my hunch is that airplanes don't even boil for a second.
The 3 minutes idea is to kill anything that may be deeply imbedded the bits of wood, leaves, and other detritus suspended in the water.
It's generally considered paranoid overkill when you consider the water will take a while to cool - it will stay in the "kill everything" temperature for quite a while in the process.
It depends on what you're trying to kill. Some bacteria perish quickly at less-than-boiling temperatures. In the wild, you have spores and other hardy organisms that require a lot more heat and time to kill.
The safe temperature for killing bacteria is about 140°F or 60°C. To get water to boil at that low a temperature requires about ⅕ atmospheric pressure, or roughly the atmospheric pressure outside the aircraft.
[1] https://academic.oup.com/jtm/article-pdf/3/1/11/5107757/jtm3...