Flying cars invented by Mr. Weasly?

[Gilderoy]

So, i was listening to the halfblood prince audiobook a few days ago and today I started with chamber of secrets again.

I was rather surprised when I noticed this.:

 

In the second book, after the Weasleys broke out Harry, Mrs. Weasley says something like: "...when her husband came home with a muggle car and told her he would just take it apart to see how it works and then bewitched it to fly."

And:

"Your son's flew an illegal car all the way to.."

 

Then in book six, when they are on their way to Kings Cross I think, there are cars from the ministry including drivers and Ron says something like: "...the ministry finally lends us these again..." (obviously hinting to the incident of the second year). 

 

 

So i wonder:

did Mr. Weasley kind of invent the flying cars or at least make them a 'ministry thing' ?

is it just something Rowling changed over time for story purposes?

Or did she just not mention the ministry had some all along and Arthur simply wanted one for himself? (So he made one)

But shouldn't wizards know how cars work (a bit), when the ministry used them all along?

 

What are your thoughts on that?

[Professor Patrick]

Who is that hiding under the invisibility cloak? Harry... Is that you? No?
Well, you must be a Muggle... And, you've found our magical community!

In that case, I think you should join us.
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[ProfessorSnape]

Who is that hiding under the invisibility cloak? Harry... Is that you? No?
Well, you must be a Muggle... And, you've found our magical community!

In that case, I think you should join us.
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Once signed in you’ll be ‘sorted’ into your Hogwarts house; where you can start creating your own personalised ‘topics’ straight away, or you can also join existing conversations with fellow fans by replying to ‘threads’ and discussions that pique your interest.

[Gilderoy]

Who is that hiding under the invisibility cloak? Harry... Is that you? No?
Well, you must be a Muggle... And, you've found our magical community!

In that case, I think you should join us.
Enrol | Sign in

Once signed in you’ll be ‘sorted’ into your Hogwarts house; where you can start creating your own personalised ‘topics’ straight away, or you can also join existing conversations with fellow fans by replying to ‘threads’ and discussions that pique your interest.