The Vax Mach Air2 and the Hoover WindTunnel Air are the exact same cleaner, I only saw this the other day when I was watching youtube videos of the WIndtunnel Air. Many Werthiem cleaners are exactly the same as other manufacturers models - there is a lot of copying of models now across brands. Cant manufacturers come up with their own designs any more. At least Dyson dont copy anyone else, its usually the other way round.
It is cheaper to buy one off someone else. So lets say Vax made that cleaner (I don't know if they did or not); they don't know how many they will sell or at what price, but then along comes Hoover and asks them to run-up a few thousand in a different colour, with the Hoover name. It's a done-deal for Vax, at any price. A bird in the hand is worth two in the bush.
Steve - the new Air 3 swivels though whereas the Windtunnel Air does not. More to the point, the original Vax Mach Air is similar. I thought they had identical suction channels but the Windtunnel Air does not. There's a previous thread regarding this on here.
Vax UK are owned by TTI - so it makes automatic sense that most Hoover products in the U.S are also available as a Vax in the UK. It was like that for years anyway - Vax Swift uprights and most of their entire uprights and cylinders were all from Dirt Devil U.S with the exception of Vax's own canister vacuum and the Bosch merged VX upright.
Where it gets confusing is when Hoover UK can't be bothered to make a vacuum cleaner of their own and pay money to brands like Dirt Devil U.S for vacuums like their Quick Vibe, redress it and then put a more expensive price on it. I was shocked when I discovered that the Dirt Devil Extreme (the same as the Hoover Alyx upright that has now been discontinued/no longer listed on Hoover UK site) is half the cost price than the version we get in the UK! Hoover's Turbo Power bagless upright isn't their own either - as one other member pointed out in a previous thread on here.
The bagged Wertheim featured on QVC is actually a Dirt Devil U.S vacuum cleaner. It also appeared here shortly in the UK as a catalogue brand/Kays brand "Swan," but without the power nozzle.