Why do the lights on the Ford Anglia and Sirius' motorbike work?

Question

Hermione tell Harry when they are discussing how Rita Skeeter is getting her information:

All those substitutes for magic Muggles use – electricity, and computers and radar, and all those things – they all go haywire around Hogwarts, there’s too much magic in the air.'

Goblet of Fire - pages 475-476

I also take from this quote that this why we only see candles,torches, and other fire driven lighting systems in the wizarding world. Houses and shops where magic is present, but probably not in same level as Hogwarts (think of the protection spells), also do not use electricity.

However, Mr. Weasley's flying Ford Anglia

and Sirius Black's flying motorbike

are both shown to have working headlights.

Since these vehicles clearly have magical enchantments and electric devices do not work around magic, how do the headlights work?

I am not asking why the vehicles themselves work as a combustion engine is mechanical, not electrical. Also, I would assume that all the buttons and levers the activate the vehicles special functions (invisibility on the car, dragon fire boot on the motorbike) are mechanical.

This related question might have some insights, particularly this answer comes closest to my line of thinking.

If something in canon can answer this, great. However, if this is just another inconsistency with JKR's application of magic universe, please support with out-of-universe context.

Answer 1

It is the amount of magic being done, not the presence of the magic in the air.

The reason electrical things don't work around Hogwarts, as you beautifully cited yourself, is that there is too much magic in the air. Not because there is any magic in the air, but because there is too much. Any magic in the air does not hurt electrical workings. For example, when Mr. Weasley came to the Dursleys' house and blasted apart the electric fireplace, it didn't stop working because of the magic in the air. Maybe if he had cast a bunch more magic or more powerful magic, it would have stopped working (along with the phone, dishwasher, etc. in the Dursleys house). Making something fly is a significant spell, but it is not nearly as magical as everything in Hogwarts, where magic is used every day and there are many powerful jinxes, hexes, and curses--Muggle repelling, anti-Apparition, DADA curse, Unplottable, etc.