The imposing and still-active volcano was used as Mt Doom in the Lord of the Rings trilogy.
Details of the mountain's movie and eruption history were among fascinating details about the three volcanoes we're here to see (Mt Tongariro and Mt Ruapehu are either side) in the 45-minute flight in a four-seater Cessna 172.
Only a day earlier, we had walked the Tongariro Crossing, a day-trek that traverses 19km between Mt Tongariro and Mt Ngauruhoe, and had watched as the small planes owned by local operator Mountain Air circled above us in the clear blue sky, which is just as sunny today.
James, and others who live and work in the area, all say the same thing: "You just never get sick of it.
"Every day something's different," he says. "The crater lakes change colour, there's more snow or less snow, the water levels change."
Despite their inviting appearance, the Blue Lake and Emerald Lakes we had lunch by the day before, 1600m above sea level, are extremely acidic from minerals in the rock and are cold - about 6C.
We can see Mt Taranaki peeking from clouds in the south, and most of Lake Taupo to the North.
Although there's still some snow - there's some hot goings-on beneath all of this. Steam pours out from the vents near the Emerald Lakes, and from the Ketetahi Springs.
James informs us that lake temperatures vary widely, depending on thermal activity underneath. The same activity, he says, changes Ruapehu's crater lake, which overflowed in 2007, from the startling turquoise we can see to deep mercury grey.
Its temperature also changes, between 14C in periods of less activity, up to about 60C.
Asked about the red dust sprinkling over the melting snow, James says the local theory is that it's not from nearby volcanic soils, but from the Sydney dust storms that brought the city to a standstill in September.
We fly around Ruapehu, the scattering of chalets well below the summer snowline of Whakapapa and Turoa. Both were fully operating skifields only weeks ago. Wind washes over the sparkling lakes, leaving an eerie trail over the water, as if ghosts are racing across the surface.
As James flies us over Tongariro, he says it is mistakenly viewed by most as the "ugly third cousin" of the more aesthetically pleasing Mt Ngauruhoe and the imposing Mt Ruapehu.
Flights above the three mountains are listed as the "most bizarre sight" in Lonely Planet's Best in Travel 2010: "Circling the volcanic peaks of Ruapehu (2797m), Ngauruhoe (2291m) and Tongariro (1968m) the World Heritage landscapes of Tongariro National Park are an otherworldly wonderland of steaming vents, blood-red-lava fields and azure crater lakes. Presented to the country in 1887 by Maori chief Te Heuheu Tukino [it] could well be the Maori people's greatest gift to modern NZ."
I'm not sure if it's "bizarre", but it certainly is awe inspiring.
Looking into the volcanic craters of mountain slopes that taper down to the Central Plateau, we get a true picture of how barren the Central Plateau really is.
The breathtaking scenes make you stop to think about just how those craters got there, their red soils a reminder of the temperamental environment and how truly at nature's mercy we are here in New Zealand.
CHECKLIST
Activity: Take a flight with Mountain Air (0800-922-812).
Sleeping: Tongariro Crossing Lodge (07-892-2688). Listed by Lonely Planet as "our pick" of places to stay in National Park.
"As pretty as a picture in white weatherboard with baby blue trim, and rambling blooms in summer," the guidebook reads.
"Rooms range from a standard double to larger self-contained rooms that include a full kitchen, although the lodge offers B&B with optional dinner (by arrangement)."
Jimmy Baker and his parents, Colin and Lynette Baker, who live on site, were great hosts.
Eating: Lonely Planet lists several local pubs, hotels and cafes but, tired after completing the Tongariro Crossing a day earlier, we decided we would have breakfast where we woke up.
We had had a continental breakfast complete with fresh fruit and yoghurt and melt-in-your-mouth mini croissants on our first morning here, but today we wanted a cooked breakfast to offset the beers from the night before.
Poached eggs, hash browns, baked beans, tomato, mushrooms and plenty of toast, with fresh fruit on the side provided just the fix before taking off for our flight above the National Park.
Beck Vass and Greg Bowker travelled around the three mountains courtesy of Mountain Air.
